The Bucks won 108-103 in overtime, halting their losing streak at two games.
Milwaukee's 7-footer missed a game with a sore back on Friday night and his production the previous three games had declined precipitously because of the injury.
Carlos Delfino, who was taken from the court on a stretcher in the Bucks' 87-74 loss to Miami on Friday, is out with neck and jaw soreness.
Bucks coach Scott Skiles said Delfino wanted to play, but is still experiencing sensitivity to light and other effects of having Udonis Haslem inadvertently land on the back of his head and neck after going up for a rebound.
Gasol had been out with a partially torn neck muscle.
Information from The Associated Press was used in this story.