Medical malpractice; Motion to amend witness list to replace an expert witness; MCR 2.401(I)(2); Good cause; Dean v Tucker; Discovery sanctions; Diligence; Prejudice; Affidavit of merit (AOM); MCL 600.2912d; Summary disposition; Dismissal with prejudice; Kirkaldy v Rim; Ottgen v Katranji

The court held that the Court of Appeals erred by requiring the circuit court to consider the Dean factors when deciding plaintiff’s motion to amend her witness list to add a replacement expert, but correctly concluded summary disposition was premature. Plaintiff filed a medical-malpractice action supported by an AOM from orthopedic expert Dr. B, and later sought to substitute Dr. H after Dr. B became unavailable for deposition. The circuit court denied amendment before granting defendants summary disposition. The court first held that the governing standard is MCR 2.401(I)(2), which permits exclusion of an unlisted witness “except upon good cause shown.” It reasoned that Dean involved “discovery sanctions that result in dismissal,” and its factors do not adequately address whether “good cause” exists to add an untimely witness because they focus primarily on misconduct rather than “a moving party’s diligence in securing an expert witness.” The court clarified that the “primary considerations” for such a motion are “(1) the diligence of the moving party and (2) the prejudice that either side would incur from granting or denying the motion.” The court next held that the circuit court abused its discretion under that standard. The record showed plaintiff was “in regular contact with Dr.” B and repeatedly tried to schedule his deposition earlier, which was “highly reflective of plaintiff’s diligence.” The circuit court also incorrectly believed discovery had closed, when it “was still open for another five months,” and it failed to articulate meaningful prejudice to defendants. Finally, because summary disposition depended on the flawed witness-list ruling that left plaintiff without an expert, the court held that summary disposition was “prematurely granted.” Reversed in part and remanded.