LOS ANGELES — Michael Beasley rejoined the Lakers after being away most of the past four weeks for “personal reasons” and coach Luke Walton said he was to throw him into the fire against his former club, the Knicks, on Friday night at Staples Center.

Beasley’s mother died just prior to Christmas. He joined her in the weeks before her death from cancer and has missed the past 18 games. Beasley, who had a strong campaign with the Knicks last year before the team opted to use its mid-level exception on Mario Hezonja, signed with the Lakers in July.

He was mostly out of the rotation until recently before his departure and Walton said he’s still expecting Beasley to make an impact with the Lakers.

“That was my message early on [to him],’’ Walton said before Beasley scored six points in the Knicks’ 119-112 win. “We got a new group of guys here. A lot of it is us learning how we play what our terminology is. I told him, keep working, I guarantee we are going to need you and use you as the season goes.

“He was just starting to play in the rotation before he left for his family. And he was good in those games. I expect when he gets his feet under him again, he helps us win games in the second half of the season.”

Beasley, who politely declined an interview before the contest, is averaging 4.4 points per game, having appeared in just 10 contests. Both the Knicks and Beasley, who visited the Knicks’ locker room after the game, may regret not reuniting for another season. Hezonja has been out of the rotation since late December and has been a big disappointment.