LeBron James returned from injury after a 13-game absence but could not prevent the Los Angeles Lakers from falling to a 118-108 defeat by the Chicago Bulls.
James, 38, scored 19 points off the bench and afterwards revealed he was recovering from a torn tendon in his right foot.
Zach LaVine hit 32 points to lead the Bulls to a seventh win in nine games.
The Lakers have dropped to ninth in the Western Conference, with seven regular season games remaining.
Teams placed seventh to 10th in the Western and Eastern conferences will contest the play-in tournament, with two teams taking the final two spots in the play-offs.
James opted to play for the Lakers after testing his foot in the warm-up but said he is still managing the injury "day to day".
He added he decided to make his return sooner than initially planned after watching his side win eight of the 13 games he missed to put themselves back in play-off contention.
"It definitely changed my mindset on me coming back and trying to be a part of this," said James.
"It just enhanced what I was trying to do as far as my workouts, as far as my treatment and everything."
Elsewhere, the Cleveland Cavaliers beat the Houston Rockets 108-91 to secure a play-off spot for the first time since James' final season with his hometown team when they lost in the 2018 NBA Finals.
Jarrett Allen scored 24 points and grabbed 14 rebounds, while Donovan Mitchell hit 22 points for the Cavs.