A plainclothes police officer, who was who shot in the head Tuesday night while pursuing a man in the Bushwick housing project, is expected to make a full recovery.

Officer Kevin Brennan, 29, was shot in the back of the head around 9 p.m. last night by a bullet that was wedged behind his right ear.

Police arrested suspected shooter Luis Ortiz nearby in his uncle's apartment three hours after the shooting.

Brennan, a six year veteran of the NYPD,  responded to a call of a man with a gun with officers Michael Burbridge and Christopher Mastoros when they encountered Ortiz and two other men in the Bushwick Houses.

Ortiz - who was wanted by the police for the New Year's Day murder of Shannon McKinney - took off and Brennan followed him into the building, where Ortiz shot him.

Brennan returned fire but did not hit Ortiz.

Brennan, who lives in Long Island with his wife and 6-week-old daughter, was immediately taken to Bellevue Hospital where the bullet was removed and is now listed in a critical but stable condition. Doctors expect him to make a full recovery.