Expert disclosure in New York is truely a black hole.  The statute does not require much by way of naming the expert.  You have to give the name and a little bit about what the expert will say.  However, the timing is completely up to court discretion.  Here is what one plaintiff did in a pinch.

Mazzurco v Gordon 2019 NY Slip Op 04930  Decided on June 19, 2019 Appellate Division, Second Department allowed plaintiff to pay his way out of a jam.

“During a pretrial conference on September 25, 2017, after jury selection, but before opening statements, at the Supreme Court’s request for a list of his witnesses, the plaintiff, for the first time, identified, among others, a damages expert. The defendants made an application, inter alia, to preclude the testimony of the proposed damages expert for failure to comply with CPLR 3101(d)(1)(i), and, upon such preclusion, to dismiss the complaint. In an order dated October 6, 2017, upon granting the plaintiff’s application for a continuance of the trial conditioned, inter alia, on the payment of the sum of $7,500 by the plaintiff’s counsel to the defendants and/or their counsel, the court denied those branches of the defendants’ application which were to preclude the plaintiff’s damages expert from testifying at trial and to dismiss the complaint upon such preclusion. The defendants appeal.

CPLR 3101(d)(1)(i) requires a party to disclose his or her expert witness and certain expert information when served with a proper demand, but does not require a response at any [*2]particular time or “mandate that a party be precluded from proffering expert testimony merely because of noncompliance with the statute” (Rowan v Cross Country Ski & Skate, Inc., 42 AD3d 563, 564; see Rivers v Birnbaum, 102 AD3d 26, 35; Saldivar v I.J. White Corp., 46 AD3d 660, 661). Trial courts are vested with broad discretion “in making determinations concerning matters of disclosure,” including imposing a penalty on a party for its failure to comply with CPLR 3101(d)(1)(i) (Arpino v F.J.F. & Sons Elec. Co., Inc., 102 AD3d 201, 209; see Rivers v Birnbaum, 102 AD3d at 52; McColgan v Brewer, 84 AD3d 1573, 1576). Generally, preclusion is unwarranted without evidence of intentional or willful failure to disclose and a showing of prejudice by the party seeking preclusion (see Rowan v Cross Country Ski & Skate, Inc., 42 AD3d at 564; Aversa v Taubes, 194 AD2d 580, 582). Here, there was no evidence that the plaintiff’s failure to disclose his damages expert was intentional or willful, and the prejudice to the defendants was alleviated by the Supreme Court’s conditional continuance of the trial to permit completion of expert disclosure along with the imposition of monetary sanctions (see Burbige v Siben & Ferber, 115 AD3d 632, 633, citing Shopsin v Siben & Siben, 289 AD2d 220; Aversa v Taubes, 194 AD2d at 582). Accordingly, the court providently exercised its discretion in denying those branches of the defendants’ application which were to preclude the plaintiff’s damages expert from testifying at trial and to dismiss the complaint upon such preclusion.”