I know someone is researching this issue right now. You're welcome. I really could have used this case a few weeks ago.
CPLR R 3025 Amended and supplemental pleadings
Alrose Oceanside, LLC v Mueller, 2011 NY Slip Op 00631 (App. Div., 2nd 2011)
Additionally, the Supreme Court providently exercised its discretion in denying that branch of the plaintiffs' motion which was for leave to amend the complaint to add a cause of action on behalf of Alrose based on concerted action liability insofar as asserted against the infant defendant. "Although leave to amend a pleading shall be freely given' in the absence of surprise or prejudice, the determination whether to grant such leave is within the court's discretion, and the [*2]exercise of that discretion will not be lightly disturbed" (Comsewogue Union Free School Dist. v Allied-Trent Roofing Sys., Inc., 15 AD3d 523, 524, quoting CPLR 3025[b]; see Fischer v RWSP Realty, LLC, 53 AD3d 595, 596). "[W]here the application for leave to amend is made long after the action has been certified for trial, judicial discretion in allowing such amendments should be discrete, circumspect, prudent, and cautious'" (Morris v Queens Long Is. Med. Group, P.C., 49 AD3d 827, 828, quoting Clarkin v Staten Is. Univ. Hosp., 242 AD2d 552, 552). "Moreover, when . . . leave is sought on the eve of trial, judicial discretion should be exercised sparingly" (Morris v Queens Long Is. Med. Group, P.C., 49 AD3d at 828; see American Cleaners, Inc. v American Intl. Specialty Lines Ins. Co., 68 AD3d 792; Comsewogue Union Free School Dist. v Allied-Trent Roofing Sys., Inc., 15 AD3d at 525). In light of Alrose's delay in moving for leave to amend its complaint to add a cause of action based on concerted action liability insofar as asserted against the infant defendant, and in light of the failure of Alrose to set forth a reasonable excuse for the delay in seeking such relief, we discern no reason to disturb the Supreme Court's determination on this issue (see American Cleaners, Inc. v American Intl. Specialty Lines Ins. Co., 68 AD3d 792; Sampson v Contillo, 55 AD3d 591; Fischer v RWSP Realty, LLC, 53 AD3d at 596-597; Cohen v Ho, 38 AD3d 705, 706; Comsewogue Union Free School Dist. v Allied-Trent Roofing Sys., Inc., 15 AD3d at 525).
Green v New York City Hous. Auth., 2011 NY Slip Op 01436 (App. Div., 2nd 2011)
While leave to amend a bill of particulars is ordinarily to be freely given in the absence of prejudice or surprise (see CPLR 3025[b]), when leave is sought on the eve of trial, judicial discretion should be exercised sparingly (see Torres v Education Alliance, 300 AD2d 469, 470; Danne v Otis El. Corp., 276 AD2d 581, 582; Reape v City of New York, 272 AD2d 533). Furthermore, where there has been an inordinate delay in seeking leave to amend to include a new injury, the plaintiff must establish a reasonable excuse for the delay and submit an affidavit to establish the merits of the proposed amendment (see Itzkowitz v King Kullen Grocery Co., Inc., 22 AD3d 636, 637; Fuentes v City of New York, 3 AD3d 549, 550; Smith v Plaza Transp. Ambulance Serv., 243 AD2d 555). The plaintiffs failed to establish a reasonable excuse for the delay. Further, the purported affirmation of the plaintiffs' expert physician submitted with the purpose of demonstrating that the "post concussion syndrome and neuropsychological impairment secondary to cerebral dysfunction" were causally linked to the infant plaintiff's accident "provided no data to indicate the basis [for the physician's] conclusion [and] was therefore speculative, conclusory, and lacking in probative value" (Paladino v Time Warner Cable of N.Y. City, 16 AD3d 646, 648; see Itzkowitz v King Kullen Grocery Co., Inc., 22 AD3d at 637; Youthkins v Cascio, 298 AD2d 386, affd 99 NY2d 638; Smith v Plaza Transp. Ambulance Serv., 243 AD2d 555).
The bold is mine.