James Blake, a retired tennis star, had the makings of a lucrative lawsuit when a New York City police officer roughed him up two years ago: vivid surveillance video, the officer’s history of force complaints, and hasty apologies from the mayor and the police commissioner. But Mr. Blake spurned a potential payout from the city for a less orthodox resolution: The city is set to announce on Wednesday that it will create a legal fellowship in Mr. Blake’s name within the agency that investigates police misconduct.

The agreement, which resolves Mr. Blake’s legal claim against the city, represents an unusual turn in a police-brutality case. Surveillance cameras caught clear film of Officer James Frascatore tackling Mr. Blake to the sidewalk in Midtown Manhattan, and the Civilian Complaint Review Board quickly determined that the officer had used excessive force.

The fellow, set to join the review board in January, will perform outreach in neighborhoods with a high volume of police complaints to help the agency close more of its investigations. Last year the agency cut short 55 percent of its investigations, mostly because victims or witnesses stopped cooperating and in other cases because the agency could not reach those people or because someone withdrew a complaint.

Mr. Blake spoke publicly soon after his arrest about the fact that most victims of police brutality have neither the money nor visibility, as he did, to elicit a public apology and a swift investigation. In compelling the city to hire the fellow, Mr. Blake sought to add an advocate for those victims — many of them in poor neighborhoods outside Manhattan — as they navigate the complaint process.