United States Court of Appeals For the Seventh Circuit ____________________ No. 20-2076 JUSTIN HERRERA, Plaintiff-Appellee, v. TERESA CLEVELAND, SAMUEL DIAZ, and ENRIQUE MARTINEZ, Defendants-Appellants. ____________________

Appeal from the United States District Court for the Northern District of Illinois, Eastern Division. No. 18-CV-6846 — Thomas M. Durkin, Judge. ____________________

ARGUED DECEMBER 1, 2020 — DECIDED AUGUST 6, 2021 ____________________

Before SYKES, Chief Judge, and BRENNAN and SCUDDER, Circuit Judges. BRENNAN, Circuit Judge. Justin Herrera, an Illinois state prisoner, filed a 42 U.S.C. § 1983 action against three correc- tional officers of the Cook County Jail for failing to protect him from assault and denying him prompt medical care. In his timely filed original complaint, Herrera named each of the defendants “John Doe” as a nominal placeholder until he 2