California courts have long emphasized that civil litigation is not meant to reward surprise. The recent decision in McDonald v. Zargaryan (2025) 177 Cal.App.5th 344 offers a clear and forceful reminder that expert disclosure rules are not procedural niceties but structural safeguards designed to protect fairness, efficiency, and the integrity of the trial process.
Factual and Procedural Background
The case arose from a low speed motor vehicle incident in 2017. The plaintiff was struck while riding a motorcycle, did not fall, walked away without assistance, and did not seek immediate medical care. The following day, he reported pain to his hip, leg, and foot, but not to his neck or groin, which came into play eventually. In the years that followed, the plaintiff asserted that the accident caused severe and lasting injuries, including disabling pain that ultimately required spinal surgery. The defense challenged that narrative, pointing to evidence that the plaintiff continued physically demanding activities such as snowboarding and rollerblading.
Expert discovery closed in September 2021. The plaintiff designated dozens of experts – none recommended spinal and/or neck surgery. Trial did not begin until nearly a year-and-a-half later in January 2023, largely due to pandemic-related delays. Yet just days before jury selection, the plaintiff consulted a new physician for the first time. That new physician recommended two major spinal surgeries. So, on the eve of trial, for the first time, surgery was on the table.
No medical emergency prompted the late consultation. There was no sudden deterioration. The plaintiff did not report new symptoms. In fact, he engaged in recreational rollerblading immediately before and after the appointment. The record showed that the physician had an existing professional relationship with plaintiff's trial counsel and had served as an expert witness for that attorney in other matters.
The defense received the report recommending surgery late on a Friday afternoon, seven days before trial. The plaintiff did not seek leave of court to augment the expert witness list. Instead, plaintiff served a supplemental disclosure without filing it and without invoking the statutory procedure required under the Code of Civil Procedure. In response, the defense promptly filed a motion to exclude the expert as untimely and prejudicial.
The trial court denied the motion, conditioning admissibility on an expedited deposition conducted at plaintiff's expense. The expert testified at trial. The jury returned a substantial verdict that included nearly two million dollars in future medical expenses and twelve million dollars in combined past and future pain and suffering. On appeal, the court vacated the judgment and held that permitting the late designated expert to testify was an abuse of discretion.
The Ruling
The opinion situates the ruling squarely within California's expert disclosure framework. That statutory scheme exists to avoid surprise at trial and to ensure that parties have the opportunity to evaluate the strengths and weaknesses of a case before jurors are empaneled. Staub v. Kiley (2014) 226 Cal.App.4th 1437, 1444. This reflects a deliberate choice to replace trial by ambush with structured disclosure and professional fairness. Deyo v. Kilbourne, (1978) 84 Cal.App.3d 771, 781.
Expert testimony presents particular risks when disclosed late. Bonds v. Roy, 20 Cal.4th 140,148. True experts carry authority that can overwhelm a jury. Their testimony often demands extensive preparation by opposing counsel, including technical study and consultation with counter experts. A rushed deposition on the eve of trial does not cure the prejudice caused by unexplained delay. It merely compounds it.
The appellate court emphasized that once the initial expert exchange and supplemental period have passed, the statute (section 2034.260, subds. (a)-(b)) requires a noticed motion and a showing of good cause to permit further augmentation. This process is not optional. It provides the court with a full view of the circumstances and gives the opposing party a meaningful opportunity to articulate prejudice. Here, no such motion was filed. No competent evidence justified the delay. The Court of Appeal characterized counsel's declaration as advocacy, not evidence, and gave it no weight.
The court acknowledged that late designations can sometimes be appropriate. Unavailability of a previously designated expert due to illness or other serious events may warrant relief. That was not this case here. The plaintiff offered no explanation beyond a pretrial consultation prompted by strategy rather than necessity.
Nor was the error harmless. The expert's testimony introduced the specter of invasive spinal surgery with significant costs and risks. The court found it reasonably probable that this testimony inflated the jury's damages award. The verdict itself supported that conclusion.
Conclusion
The decision underscores an important principle for trial courts and litigants alike. Judicial discretion has its limits. Conditioning admissibility on a rushed deposition does not substitute for statutory compliance where no good cause exists. Fairness at trial requires more than speed. It requires adherence to rules designed to ensure both sides arrive prepared, informed, and on equal footing.
For practitioners, the lesson is direct: late expert disclosures without court approval carry substantial risk, even where the trial courts attempt to mitigate prejudice. For judges, the case serves as a reminder that enforcing disclosure statutes protects not only the opposing party, but also the legitimacy of the verdict itself. In vacating the judgment and remanding for a new trial, the court reaffirmed that California civil practice values fairness over gamesmanship.
