Kemba Walker (left knee) misses Game 4 vs. Nets

Celtics guard suffered a left knee bone bruise in Game 2 that left him 'questionable' for Sunday's action.

Kemba Walker’s struggles to keep his ailing left knee in full game shape have played into the Celtics’ underwhelming season showing. And with a crucial Game 4 in front of Boston, the former All-Star point guard will be watching this one from the sidelines.

Walker (knee) and center Robert Williams III (ankle) sat out after playing in the first three games of the series, joining Brown (season-ending wrist surgery) on the injury report. Boston lost Game 4 to Brooklyn, 141-126, to fall into a 3-1 series hole.

Game 4 Recap: Nets 141, Celtics 126

Walker had been listed as “questionable” on the injury report before ultimately being ruled out. Romeo Langford started in Walker’s place and finished with nine points on 2-for-6 shooting as well as a rebound and an assist.

Walker, in his second season with the Celtics after eight in Charlotte, only appeared in 43 of 72 regular-season games. He averaged 19.3 points (42.0 FG%; 36.0 3P%), 4.0 rebounds and 4.9 assists – his weakest offensive season since 2014-15, the last time he posted fewer than 20 ppg.