Ordered that the order, as amended, is reversed, on the law, with costs, the motion for summary judgment is granted and the complaint is dismissed insofar as it is asserted against the defendant Yasphal Arya and the action against the remaining defendant is severed.
In supporting his motion for summary judgment the appellant submitted a medical affidavit prepared by Dr. Richard S. McCray which sufficed to establish prima facie his entitlement to judgment as a matter of law, thereby shifting the burden to the plaintiff to lay bare his proof and demonstrate the existence of a triable issue of fact (see, Winegrad v. New York Univ. Med. Ctr., 64 N.Y.2d 851; Simms v. North Shore Univ. Hosp., 192 A.D.2d 700). Under the circumstances of this case, the plaintiff was required to come forward with expert medical opinion evidence in order to demonstrate the merit of his action (see, Fiore v Galang, 64 N.Y.2d 999). However, the plaintiff merely submitted an unsigned, unsworn letter of a physician in opposition to the motion. The letter did not constitute evidentiary proof in admissible form sufficient to defeat the motion for summary judgment (see, Simms v. North Shore Univ. Hosp., supra). Sullivan, J.P., Rosenblatt, Altman, Hart and Friedmann, JJ., concur.