¶ 1 Jerry Ferguson appeals from the judgment of sentence imposed following his conviction of aggravated assault and recklessly endangering another person. See 18 Pa.C.S. §§ 2702, 2705 (respectively). Ferguson claims that the trial court erred in allowing the Commonwealth to introduce evidence of which he had no pretrial notice to impeach a defense witness in violation of the disclosure mandate of Brady v. Maryland, 373 U.S. 83, 83 S.Ct. 1194, 10 L.Ed.2d 215 (1963), and its progeny. Ferguson further claims that the jury’s verdict was against the weight of the evidence. Because, inter alia, we do not find the disputed evidence constitutionally material, we conclude that the Commonwealth’s failure to produce the disputed evidence prior to trial did not constitute a Brady violation. Accordingly, we affirm the judgment of sentence.
¶ 2 This matter arises out an assault by multiple perpetrators when one or more of them took offense to the victim’s sarcastic response to a request for a cigarette. On the evening of August 26, 2002, victim Jason Cambra left his apartment to get bread, milk and snacks at the local Dairy Mart convenience store. After leaving the store, Cambra encountered Ferguson who, along with cohort Ricardo Jones and three others, were “hanging out” on the street. As Cambra walked past, one of them asked, ‘To, do you have a cigarette?” to which Cambra replied ‘To, I don’t smoke.” Finding Cambra’s response offensive, Ferguson struck Cambra in the head, knocking him to the ground and, with the others, continued to punch and kick him until Cambra lay unconscious. Cambra suffered multiple compressed facial fractures requiring surgical repair. Due to the trauma he sustained, Cambra has no recollection of the attack.
¶ 3 At trial, the parties produced conflicting testimony to account for who participated in the beating. In its case-in-chief, the Commonwealth called Ferguson’s cousin, Ricardo Jones, and an acquaintance, Sylvester Tate. Tate testified that he had been walking down an alley adjacent to the Dairy Mart when he saw Cambra walking near a group of five young men, including Ferguson and Jones. Tate saw Ferguson speak to Cambra and then strike him in the face, causing him to fall to the ground. Tate testified that the group of men then kicked Cambra for a couple of minutes while he lay unconscious.
¶ 4 The Commonwealth next offered the testimony of Paul Davis. Davis stated that he was present at Chrisandra’s bar, located across the street from the Dairy Mart. As he exited the bar, Davis observed *405a “white person” and a “black dude” talking loudly near a group of young men. The white man then began to walk away when one of the young men, who Davis recognized as Chaz Mathis, hit him “from the blind side.” Davis further stated that Ferguson was present and kicked the man repeatedly. Davis also testified that Jones participated in the attack.
¶5 Ferguson called Ricardo Jones, his cousin, who testified that he alone encountered Cambra outside of the Dairy Mart as he walked to his grandmother’s house to meet Ferguson. Jones testified that it was he who approached Cambra and asked for a cigarette and then punched him in the head. Jones stated further that after Cambra fell to the ground, he “got on top of’ him and beat him. As a result of this incident, Jones pled guilty to charges against him.
¶ 6 After Ferguson’s counsel finished his direct examination of-Jones, the Commonwealth introduced a letter Jones had written to the police stating that he was innocent of the beating and that Sylvester Tate and Chaz Mathis were the responsible parties.' At sidebar', defense counsel objected, stating that he had no previous knowledge of the letter and that the Commonwealth’s impromptu submission amounted to “being ambushed here with information I don’t have a copy of, I know nothing about.” The court granted a ten minute recess for counsel to read the letter.
¶ 7 When the proceedings resumed, the Commonwealth stated for the record its reasons for not disclosing the letter at a previous time. The Commonwealth avowed that it had received the evidence from the police department only two days prior and “did not give [the letter] much attention at the time.” During Jones’ testimony, a police detective gave a copy of the letter to the Commonwealth, prompting its presentation to the court. Defense counsel countered that the Commonwealth’s tardy disclosure was a discovery violation.in fight of his timely discovery request and the Commonwealth’s ongoing responsibility to disclose any inculpatory or exculpatory information. Counsel further stated that he would not have called Jones to testify or would have done so only upon Ferguson’s own introduction of the prior inconsistent statements made in the letter to ensure that Jones could maintain credibility in fight of the apparent conflicting evidence.
¶ 8 The court overruled Ferguson’s objections and admitted the letter into evidence, reasoning that Ferguson had the opportunity to interview Jones prior to his taking the stand and should have ascertained whether such evidence existed at that time. Following the court’s ruling, the Commonwealth cross-examined Jones. In his testimony, Jones admitted to writing the letter stating his own innocence and implicating others in order to escape punishment. Jones further stated that the allegations he made in the letter were false and after realizing his error in lying, he confessed to beating Cambra. Despite his previous fabrication, Jones maintained that his testimony was true and was not influenced by his familial relationship with Ferguson.
¶ 9 On September 12, 2003, the jury convicted Ferguson of aggravated assault and recklessly endangering another person. On September 23, Ferguson filed a motion for a new trial based upon the nondisclosure of Jone’s letter by the Commonwealth. The court denied the motion and subsequently sentenced Ferguson to ten to twenty years’ incarceration. Thereafter, Ferguson filed the instant appeal raising two questions for our review:
A. Is the appellant entitled to a new trial under Brady v. Maryland, 373 U.S. 83, 83 S.Ct. 1194, 10 L.Ed.2d *406215, 83 S.Ct. 1194 (1963), and its progeny where the Commonwealth failed to provide to defense counsel information which it had in its possession that was favorable to the accused and material to the question of guilt?
B. Was the verdict against the weight of the evidence where a third party testified to his responsibility for the injuries to the victim, the victim could not identify Appellant as his assailant, and the Commonwealth presented no testimony to corroborate that [Ferguson] caused the injuries.
Brief for Appellant at 4 (some capitalization removed).
¶ 10 Ferguson’s first question challenges the trial court’s exercise of discretion in allowing the letter written by Jones into evidence when the Commonwealth failed to disclose the letter prior to trial. Ferguson argues that because the letter inculpated two assailants other than the defendant and contradicted the witness’s admission that he himself had assaulted the victim, it is exculpatory of the defendant and might have prompted a change in defense strategy had it been produced prior to the witness’s testimony. Brief for Appellant at 11. He concludes accordingly that its admission violated both Brady and Pennsylvania Criminal Rule 573, which effectively codifies the Brady rule. We conclude that, under the circumstances of this case, the letter is not exculpatory and therefore is not “constitutionally material” within the meaning of the Brady line of cases. Accordingly, the Commonwealth’s failure to disclose it, although regrettable, does not constitute a denial of due process under the Fourteenth Amendment or a cognizable violation of Rule 573.
¶ 11 Rule 573 requires that the Commonwealth “shall disclose to the defendant’s attorney all ... evidence favorable to the accused that is material either to guilt or to punishment, and is within the possession or control of the attorney for the Commonwealth.” Pa.R.Crim.P. 573(B)(1)(a). Similarly, Brady provides that “the suppression by the prosecution of evidence favorable to an accused upon request violates due process where the evidence is material either to guilt or to punishment[.]” 373 U.S. at 87, 83 S.Ct. 1194. In this context, however, the term “material” has been variously defined, expanded and, ultimately, consolidated in a manner that appears to narrow its reach. See generally U.S. v. Agurs, 427 U.S. 97, 96 S.Ct. 2392, 49 L.Ed.2d 342 (1976); see also Strickler v. Greene, 527 U.S. 263, 296-301, 119 S.Ct. 1936, 144 L.Ed.2d 286 (1999) (Souter, J., concurring and dissenting); U.S. v. Bagley, 473 U.S. 667, 682, 105 S.Ct. 3375, 87 L.Ed.2d 481 (1985); Strickland v. Washington, 466 U.S. 668, 694, 104 S.Ct. 2052, 80 L.Ed.2d 674 (1984).
¶ 12 This evolving definition is crucial to the disposition of cases such as this one, where the evidence withheld by the Commonwealth, although of significance in pretrial planning by the defense, is of limited value in impeaching the verdict. Initially, the United States Supreme Court defined materiality with reference to the form and extent of the defendant’s request for disclosure. See Agurs, 427 U.S. at 103-07, 96 S.Ct. 2392. Hence, whether counsel had made a specific request, general request, or no request at all assumed controlling significance in determining the extent to which the evidence not disclosed was constitutionally material. See Agurs, 427 U.S. at 103-07, 96 S.Ct. 2392 (prescribing standards of materiality based on specificity of defense request for disclosure). Evidence the defendant had specifically requested that the prosecution then failed to produce *407was adjudged by a different measure of materiality than evidence withheld where the defendant had not requested disclosure. See id. More recently, however, the Court consolidated the definition, allowing only tacit recognition of the nature of the defendant’s request. See Bagley, 473 U.S. at 682, 105 S.Ct. 3375 (citing Strickland, 466 U.S. at 694, 104 S.Ct. 2052).
We find the Strickland formulation of the Agwrs test for materiality sufficiently flexible to cover the “no request,” “general request,” and “specific request” cases of prosecutorial failure to disclose evidence favorable to the accused: The evidence is material only if there is a reasonable probability that, had the evidence been disclosed to the defense, the result of the proceeding would have been different.
Id. (emphasis added). The Court further defined reasonable probability as “a probability sufficient to undermine confidence in the outcome.” Id.
¶ 13 In the wake of Bagley, the Supreme Court of Pennsylvania continued to draw the earlier distinctions based on the specificity of the defendant’s request for disclosure only for a limited time. See Commonwealth v. Green, 536 Pa. 599, 640 A.2d 1242 (1994) (applying Agwrs standard of materiality based on general request for disclosure); Commonwealth v. Moose, 529 Pa. 218, 602 A.2d 1265 (1992) (same); but see Commonwealth v. Santiago, 405 Pa.Super. 56, 591 A.2d 1095, 1115-17 (1991) (recognizing and applying Bagley standard). More recently, however, our Supreme Court has relied consistently on the consolidated standard in Bagley, without reference to the form of the original request for disclosure. See Commonwealth v. Chambers, 570 Pa. 3, 807 A.2d 872, 887 (2002) (quoting Bagley standard of materiality); Commonwealth v. Simmons, 569 Pa. 405, 804 A.2d 625, 636-37 (2001) (same); Commonwealth v. Paddy, 569 Pa. 47, 800 A.2d 294, 305-06 (2002) (same); Commonwealth v. Burke, 566 Pa. 402, 781 A.2d 1136, 1141 (2001) (same); Commonwealth v. Strong, 563 Pa. 455, 761 A.2d 1167, 1174 (2000) (same); see also Commonwealth v. Grant, 572 Pa. 48, 813 A.2d 726, 730 (2002) (citing Paddy). Although the Court has not expressly disavowed the standard in Agwrs, on which Ferguson impliedly relies, Brief for Appellant at 16 (citing Moose, supra), its current application of the standard in Bagley suggests its adoption of the standard sub silentio. We conclude, accordingly, that the standard of materiality enunciated in Bagley applies to all Brady claims raised in Pennsylvania. Thus, in the context of pre-trial disclosure, “evidence is material only if there is a reasonable probability that, had the evidence been disclosed to the defense, the result of the proceeding would have been different.” 473 U.S. at 682, 105 S.Ct. 3375.
¶ 14 Nevertheless, regardless of the caselaw cited, one precept has remained constant: “If there is no reasonable doubt about guilt whether or not the additional evidence is considered, there is no justification for a new trial.” Green, 640 A.2d at 1245 (quoting Agurs, 427 U.S. at 112-13, 96 S.Ct. 2392). “The mere possibility that an item of undisclosed information might have helped the defense, or might have affected the outcome of the trial, does not establish materiality in the constitutional sense.” Chambers, 807 A.2d at 887. Rather, “material evidence” must be favorable to the accused “so that, if disclosed and used effectively, it may make the difference between conviction and acquittal.” Santiago, 591 A.2d at 1117 (quoting Bagley, 473 U.S. at 676, 105 S.Ct. 3375).
¶ 15 Applying this standard to the facts of this case, we find no basis for the *408award of a new trial that Ferguson requests. The proffered impeachment evidence on which the defendant relies is not sufficiently favorable, and its suppression was not sufficiently prejudicial, to satisfy the constitutional threshold of materiality. This is so because the evidence fails entirely to discredit any of the eyewitness testimony upon which Ferguson’s conviction is based. Notwithstanding changes in trial strategy defense counsel may have made in light of Jones’s letter to avoid or ameliorate the resulting injury to his credibility, direct evidence legally sufficient to sustain Ferguson’s conviction would remain unchanged. That evidence establishes beyond any reasonable doubt that Ferguson was one of a group of perpetrators who brutally assaulted Jason Cambra in broad daylight in view of two sworn eyewitnesses. This distinction is critical, for unlike the scenario in Green on which Ferguson relies heavily, Ferguson’s conviction was not based merely on circumstantial evidence. See 640 A.2d at 1245 (finding material undisclosed statements suggesting guilt of third party where defendant’s trial did not include eyewitness testimony and defendant’s conviction was based solely on circumstantial evidence and inferences).
¶ 16 The evidence in this case is, by contrast, much more substantial. Sylvester Tate, who had been Ferguson’s best friend since the two were in first grade, N.T., 9/11/03, at 92, stood only several yards away, watching as the melee began, N.T. 9/11/03, at 100. He gave a detailed account of what happened, recalling that Jerry Ferguson and Ricardo Jones were among a group of four teenagers who challenged the victim as he walked down the street carrying groceries. N.T., 9/11/03, at 97-99. He heard Ferguson say something to the victim as he passed and then saw him hit the victim in the head with sufficient force that he collapsed to the ground without even a chance to exchange blows. N.T., 9/11/03, at 100-01. Tate continued to watch as all of the youths, Ferguson still among them, began to kick and stomp the victim all over his body. N.T., 9/11/03, at 101-02, 116. Tate’s testimony remained consistent, unshaken even on cross-examination, N.T., 9/11/03, at 111-15.
¶ 17 Similarly, eyewitness Paul Davis also recalled the melee, confirming that Ferguson joined in kicking and stomping the victim as he lay on the pavement. N.T., 9/12/03, at 7. Although his recollection of the first blow, which he said was struck by another member of the group, N.T., 9/12/03, at 6, varied from Tate’s recollection, it established nonetheless that Ferguson had been one of the victim’s assailants. Although this variation might assume greater significance had the offense arguably been committed by only a single assailant, the evidence here is overwhelming that the offense was committed by at least four people. Hence, Davis’s recollection that someone other than Ferguson struck the first blow does little to detract from the evidence, on which both witnesses agreed, that Ferguson participated in an aggravated assault upon the victim. Indeed, the eyewitnesses’ testimony did not vary on that point. Unlike the verdict in Green, based on circumstantial evidence and subject to question based on a co-defendant’s “jailhouse” admission, the verdict here is grounded on the testimony of eyewitnesses, both of whom attested to Ferguson’s role in the assault. Regardless of whether the defense had chosen to call Ricardo Jones to attest to his own role in the assault, his testimony of his own involvement would not negate the testimony of the Commonwealth’s witnesses that Ferguson too was involved. Accordingly, the fact that Jones’s credibility could be called into question based on a letter not disclosed to the defense cannot be deemed so *409critical as to show “a reasonable probability that, had the evidence been disclosed to the defense, the result of the proceeding would have been different,” Bagley, 473 U.S. at 682, 105 S.Ct. 3375 (citing Strickland, 466 U.S. at 694, 104 S.Ct. 2052); nor can it be said to “make the difference between conviction and acquittal.” Santiago, 591 A.2d at 1117 (quoting Bagley, 473 U.S. at 676, 105 S.Ct. 3375).
¶ 18 Because we do not find Jones’s letter sufficient to yield so great a difference, even if disclosed, we cannot find it “material” within the meaning of Brady and its progeny. Consequently, we find no due process violation and no ground on which to grant a new trial. Although we do not condone the apparent lack of diligence that prompted the Commonwealth’s nondisclosure, we do not find it a sufficient reason on which to grant a new trial. See Green, 640 A.2d at 1245 (quoting Agurs, 427 U.S. at 112-13, 96 S.Ct. 2392) (“If there is no reasonable doubt about guilt whether or not the additional evidence is considered, there is no justification for a new trial.”).
¶ 19 In Ferguson’s second question, he challenges the verdict as against the weight of the evidence. We note, however, that in order to prevail on such a claim, an appellant must first preserve the underlying issue before the trial court pursuant to Rule 607 of the Pennsylvania Rules of Criminal Procedure. Pa.R.Crim.P. 607 Comment (“The purpose of this rule is to make it clear that a challenge to the weight of the evidence must be raised with the trial judge or it will be waived.”). In his motion for a new trial, Ferguson failed to raise this claim, nor does he cite to any passage of the record demonstrating that he raised the issue during trial. See Pa.R.Crim.P. 607(A)(1), (2). Therefore, we find this claim to be waived and decline to consider it further.
¶ 20 For the foregoing reasons, we affirm the judgment of sentence.
¶ 21 Judgment of sentence AFFIRMED.
¶ 22 BENDER, J., files a Dissenting Opinion.