LOS ANGELES -- New York Knicks big man Bobby Portis was ejected in the first half of Tuesday's game against the Los Angeles Lakers for forcefully knocking Kentavious Caldwell-Pope across the head while the Lakers' guard was airborne.

The Lakers led the Knicks 39-30 with 8:02 remaining in the second quarter when Caldwell-Pope streaked in for a transition layup off a Rajon Rondo feed when Portis, trailing from behind, swung his right arm, landing the inside of his bicep with the top of Caldwell-Pope's head.

The blow sent Caldwell-Pope's headband flying and the play ended with Caldwell-Pope on the floor wincing in pain while several of his Lakers teammates -- LeBron James and Rondo among them -- confronting Portis.

Following an official's review, Portis was assessed a Flagrant 2 foul and ejected.

Caldwell-Pope, after rubbing the sides of his head while being attended to by Lakers head athletic trainer Nina Hsieh as he stayed on the floor, subbed out of the game to receive further medical attention.

Lakers guard Danny Green was elected to shoot free throws in Caldwell-Pope's place, going 1-for-2.

The Lakers said that Caldwell-Pope underwent a concussion evaluation which was negative. He checked back in with 2:21 remaining in the third quarter.

The physical play continued in the third quarter when former Laker Reggie Bullock was called for a Flagrant 1 foul for a horse collar-like takedown of L.A. center JaVale McGee.