dissenting.
Fully aware of the deference that must be given trial judges in the exercise of their discretion in controlling discovery, I nevertheless conclude that it was an abuse of discretion to prevent Dr. Davidson from testifying as an expert witness.
The majority disputes the fact that defendants had actual knowledge that Dr. Davidson was one of the two principal treating physicians (the other being Dr. Prelutsky, one of the defendants) as far back as November 1990, more than three years before trial. Although it is true that plaintiff failed to list Dr. Davidson as one of the treating physicians in response to interrogatories, defense counsel admitted in oral argument that his co-counsel had been present at Dr. Davidson’s deposition in early 1991. Moreover, defense counsel, who had been “noticed-up” for the deposition, was necessarily aware that it was taken by plaintiff for the purpose of preserving the doctor’s testimony for use at trial. For defendants now to claim that they were blind sided by the revelation that Dr. Davidson was a treating physician is sheer fiction, and the trial court’s countenance of the claim is at the root of the abuse of discretion.
This is not a case in which a party failed to respond to a request to disclose expert witnesses expected to be called at trial. In that instance, a trial court could properly preclude the expert testimony of a non-disclosed expert because the opposing party was given no real opportunity to depose that expert or otherwise prepare for the testimony. Here, however, the plaintiff fielded a request for disclosure of experts with the timely response that any of her treating physicians might be called as experts on the issues of standard of care, causation and damages. At that point, defendants were on notice that Dr. Davidson, a treating physician, was potentially an expert witness, and it would have behooved them to take his deposition, themselves, before discovery was cut off. Instead, defendants shielded themselves with plaintiffs technical non-compliance in answering the original interrogatories about treating physicians. In doing so, the defendants, in effect, sandbagged the plaintiff and abused the discovery process no less than did the plaintiff herself.
*651Furthermore, sanctions against a party for violations of discovery rules should not be imposed unless the opposing party has been prejudiced by the violations. Dunn v. Wal-Mart Stores, Inc., 909 S.W.2d 728, 733 (Mo.App.1995); DeLaporte v. Robey Building Supply, Inc., 812 S.W.2d 526, 533 (Mo.App.1991); State ex rel. Missouri Highway and Transportation Commission v. Fully, 737 S.W.2d 241, 245 (Mo.App.1987). In this case, the defendants, having full knowledge of Dr. Davidson’s involvement as a treating physician and having been given notice that treating physicians may be called as experts, should be hard pressed to claim prejudice.
Under these circumstances, the trial court should have allowed the late endorsement of Dr. Davidson as an expert witness and offered defendants the opportunity to take the doctor’s deposition. There was ample time as evidenced by the fact that on March 29, 1993, plaintiffs counsel sent a letter to defendants clarifying Dr. Davidson’s status as both a treating physician and an expert witness, but that the trial was not held until eleven months later, in February 1994.
The prejudice to plaintiff resulting from the trial court’s abuse of discretion is obvious. Rarely is a treating physician willing to testify against another treating physician. Unquestionably, it is testimony that is much more effective than that from hired, out-of-town experts who were not present at the time the treatment was rendered.
For these reasons, I would reverse the judgment of the trial court and remand for a new trial.