In the New York City police officer’s recollection, a man who was leaning against a pillar outside the Grand Hyatt Hotel in Midtown in 2015 looked just like the person he was supposed to arrest, a suspect in a credit card fraud ring who the officer had been told might be armed.

Appearing at a disciplinary hearing on Tuesday at Police Headquarters, the officer, James Frascatore, said that when a supervisor told him to move in, he charged across East 42nd Street, grabbed the man’s arm and swiftly took him to the ground. It was his first public account of the encounter with the man, who turned out to be James Blake, the retired professional tennis player.

The Civilian Complaint Review Board, which investigates accusations of police abuse and misconduct, is prosecuting Officer Frascatore on a departmental charge of using excessive force to take down Mr. Blake. A Police Department judge will decide the case, and Commissioner James P. O’Neill will determine any punishment. The board is seeking to have the commissioner fire Officer Frascatore, who has been reassigned to an administrative job in the Detective Bureau.

The incident — which was captured on surveillance video — highlighted the kinds of encounters with the police that many black and Latino civilians have complained about for years but that have rarely resulted in officers facing discipline, even after drawn-out proceedings. Mr. Blake, who was in town for the United States Open, had nothing to do with the theft.