A New York Police Department officer was stripped of his gun and badge as Mayor Bill de Blasio and Police Commissioner William J. Bratton issued swift apologies on Thursday for the rough arrest of James Blake, the retired tennis star, after he was misidentified as a suspect in a fraudulent credit card ring.

Criticism swirled over whether Mr. Blake had been mistreated because he was biracial. But it was Mr. Bratton’s acknowledgment that excessive force may have been used when an officer threw him to the ground that put a renewed national focus on the everyday arrest tactics long criticized by members of minority groups. The officers failed to report the mistaken arrest, as they were required to do, raising the possibility that it would not have come to light had Mr. Blake not spoken out.

The incongruity of a Harvard-educated professional athlete being manhandled by six white plainclothes officers on a sidewalk in Midtown Manhattan quickly became an embarrassment for the Police Department and a headache for Mr. de Blasio, exposing the kind of unprovoked aggression that he and elected leaders across the country have sought to stamp out.

The officer’s decision to throw an unarmed, compliant man to the ground added to the sense that black people are often roughed up by the police out of view, with few resources to bring attention to their grievances. In a sign of the shifting discourse on race and policing, Mr. de Blasio and Mr. Bratton moved with unusual speed to contact Mr. Blake to apologize. But the gestures also raised questions about whether they would have moved so swiftly if the encounter had not involved a well-known figure.