Plaintiff-appellant Ricardo Brenes appeals from the judgment of the district court, granting summary judgment to the defendants-appellees. At the time the parties moved for summary judgment, Brenes was proceeding pro se. We assume the parties' familiarity with the underlying facts and the procedural history of this case, as well as with the issues raised on appeal.

I. First Amendment Retaliation Claim

We affirm in part and vacate in part the district court's grant of summary judgment to the defendants-appellees with respect to Brenes's First Amendment retaliation claim. Brenes does not challenge the district court's analysis in dismissing his claims against defendants-appellees D'Amore Ferrandino, Turetsky, Ferrandino, Emanuelson, and Stancik, and we therefore consider any objection to be waived. We also conclude that Brenes's claim against defendant-appellee Stoopack is barred by the three-year statute of limitations for actions in New York pursuant to 42 U.S.C. § 1983. See Ormiston v. Nelson, 117 F.3d 69, 71 (2d Cir. 1997). Brenes filed his complaint on June 8, 2001, and he does not allege that Stoopack undertook any retaliatory actions against him on or after June 8, 1998. Accordingly, we affirm the district court's grant of summary judgment on Brenes's retaliation claim with respect to these defendants.

Brenes alleges that the remaining defendants-appellees, Frank, Ward, Crew, and the municipal defendants, retaliated against him while he was a teacher at Norman Thomas High School ("Thomas") for his participation in a December 21, 1997 New York Post article that discussed attendance fraud in New York City schools. Brenes alleges that in retaliation for the Post article, (1) Frank, the principal of Thomas, began giving him negative classroom evaluations starting in October 1998, (2) Ward, the Manhattan Superintendent, had a designee visit Brenes's class in December 1998 who also gave him a negative evaluation, (3) Frank, Ward, and School's Chancellor Crew contributed to the decision to terminate him in January 1999, initially without providing him with the 60 days' notice required under the applicable law, and (4) after Brenes was offered the opportunity to work at Thomas for an additional 60 days, Frank terminated him again on February 1, 1999 for refusing an assignment. We conclude that the district court erred in holding that there was inadequate evidence to support a retaliation claim against Frank, but we affirm the district court's grant of summary judgment to the other defendants.

Although Frank's first negative evaluation of Brenes occurred nearly ten months after the publication of the Post article, a transfer form indicates that on February 3, 1998, less than two months after the Post article was published, Frank also attempted to reject Brenes's appointment to teach at Thomas. We conclude that the timing of this attempt is probative of retaliatory animus. See Burkybile v. Bd. of Educ. of Hastings-on-Hudson Union Free Sch. Dist., 411 F.3d 306, 314 (2d Cir. 2005). Moreover, Frank stated in the form that she was denying Brenes's appointment because no vacancy existed at Thomas, explaining that the slot was temporarily created by the reassignment of a teacher who had the right of return in September. Frank's objections were overruled by the Office of Staffing Services at the Board of Education, which stated, "[h]e remains in your school as an appointed teacher. If he is excessed in June, so be it." Brenes was not excessed, however, and returned to Thomas for the next school year. A reasonable jury could infer from these facts that Frank expected that Brenes's position would disappear in June, and that she therefore had no incentive to further retaliate against him until it became clear that he would be returning to Thomas. When considered in this light, Brenes's series of negative performance evaluations at the start of the next school year is suspicious and could plausibly support an inference of retaliation, particularly given that Brenes previously received only satisfactory evaluations from prior supervisors and Frank. Cf. Espinal v. Goord, 554 F.3d 216, 228 (2d Cir. 2009) (holding that a six-month lapse between the dismissal of a plaintiff's lawsuit and an allegedly retaliatory beating by a police officer who was a defendant in the suit supported an inference of causation because "[i]t is plausible that the officers waited to exact their retaliation at an opportune time"). Accordingly, the district court erred in granting summary judgment to Frank on Brenes's retaliation claim.

We conclude, however, that there is inadequate evidence in the record to support Brenes's retaliation claim against Ward and Crew. First, these defendants' actions against Brenes occurred approximately a year after the publication of the Post article, and there is no evidence that either Ward or Crew took any action against Brenes in the months following the article's publication. Second, Brenes submitted no evidence that Ward or Crew held retaliatory animus towards Brenes, knew or should have known that their subordinates were retaliating against Brenes, ordered their subordinates to retaliate against Brenes, or created a policy or custom of permitting retaliation for teachers' exercise of their First Amendment rights. See Colon v. Coughlin, 58 F.3d 865, 873 (2d Cir. 1995). Likewise, because there is no evidence of a municipal policy or custom of First Amendment retaliation, there is inadequate evidence to support Brenes's claim against the municipal defendants. See Powell v. Gardner, 891 F.2d 1039, 1045 (2d Cir. 1989). We therefore affirm the grant of summary judgment to Ward, Crew, and the municipal defendants.

II. Due Process Claim

We also vacate the district court's denial of leave to amend the complaint to assert a due process claim arising from Brenes's termination. We hold that the district court erred in finding that Brenes's due process claim is barred by claim preclusion, and conclude that evidence in the record might support Brenes's claim.

The district court found that claim preclusion applied to Brenes's due process claim because he previously challenged his termination through an Article 78 proceeding in the New York Supreme Court, in an action against the Board of Education. The Board of Education raised two defenses in the Article 78 proceeding, arguing that Brenes had failed to exhaust administrative remedies and that his action was barred by the statute of limitations. The court dismissed Brenes's action without explanation. We have held that a "plaintiff is not barred [by claim preclusion] from seeking damages, in federal court, on civil rights claims by reason of a prior judgment on the same underlying facts in an Article 78 proceeding requesting injunctive or affirmative relief." Davis v. Halpern, 813 F.2d 37, 39 (2d Cir. 1987). Accordingly, Brenes's action is not barred by claim preclusion. Issue preclusion is likewise not a bar, because the Article 78 proceeding did not "necessarily . . . decide[]" any issue relevant to Brenes's due process claim. Burgos v. Hopkins, 14 F.3d 787, 792 (2d Cir. 1994) (internal quotation marks omitted). In particular, the court made no explicit determination as to the constitutionality of Brenes's dismissal, whether Brenes had tenure, and whether the Board followed the correct procedures in dismissing him. See O'Connor v. G R Packing Co., 53 N.Y.2d 278, 284, 440 N.Y.S.2d 920, 423 N.E.2d 397 (1981) (explaining that a "less than explicit holding in [a] prior action should not be given preclusive effect").

Moreover, we conclude that evidence in the record might support Brenes's due process claim. Brenes alleges that he was tenured at the time of his termination, giving him a right to procedural protections before he could be fired. See O'Connor v. Pierson, 426 F.3d 187, 196 (2d Cir. 2005). He relies on a theory of tenure by estoppel, which "results when a school board accepts the continued services of a teacher or administrator, but fails to take the action required by law to either grant or deny tenure prior to the expiration of the teacher's probationary term" Speichler v. Bd. of Co-op. Educ. Servs., 90 N.Y.2d 110, 114, 659 N.Y.S.2d 199, 681 N.E.2d 366 (1997) (internal quotation marks omitted). The defendants-appellees' answer concedes that Brenes began his probationary term on September 2, 1997, which might have given him tenure by estoppel by the time he was terminated. The defendants-appellees now assert that this concession was in error and that Brenes worked as a regular substitute teacher rather than as a probationary teacher during the September 1997 school term. The defendants-appellees never moved to amend their answer, however, and are therefore bound by their judicial admission. See Gibbs ex rel. Estate of Gibbs v. CIGNA Corp., 440 F.3d 571, 578 (2d Cir. 2006). Moreover, the evidence in the record does not clearly establish when a teaching position or appointment qualifies as "probationary" or "regular substitute." Accordingly, we vacate the district court's denial of leave to amend. We express no opinion as to whether the district court should permit the defendants-appellees to amend their answer and what impact any such amendment would have on Brenes's claim. Cf. United States v. McKeon, 738 F.2d 26, 31 (2d Cir. 1984) ("The law is quite clear that [superseded] pleadings constitute the admissions of a party-opponent. . . .").

III. Remaining Arguments on Appeal

Brenes's notice of appeal also challenges the district court's denial of his motion for the judge's recusal and denial of his motion to take additional depositions pursuant to Rule 56(f). Brenes did not pursue these arguments in his briefing, and we therefore consider them waived. See Norton v. Sam's Club, 145 F.3d 114, 117 (2d Cir. 1998) ("Issues not sufficiently argued in the briefs are considered waived and normally will not be addressed on appeal.").

For the reasons discussed, we AFFIRM the grant of summary judgment to D'Amore Ferrandino, Turetsky, Ferrandino, Emanuelson, Stancik, Crew, Ward, and the municipal defendants with respect to Brenes's First Amendment retaliation claim. We VACATE the grant of summary judgment to Frank with respect to Brenes's First Amendment retaliation claim. We also VACATE the district court's denial of leave to amend the complaint to assert a due process claim. We REMAND for further proceedings consistent with this order.