Just before tip-off, the team announced that Kyle Kuzma (right heel contusion) would also miss the game.
The Lakers lost 114-104, snapping a two-game winning streak that dated back to the return of starting point guard Dennis Schroder. Schroder had missed the Lakers' previous four games, all of them losses, while being sidelined because of a violation of the health and safety protocols because of contact tracing.
"We play so well the last two games, we get back into a rhythm, and then we find out today that two of our big guns were out,'' LeBron James said. "It's definitely deflating, especially when you were playing poorly and then you get in a good rhythm."
Gasol, 36, was signed to a two-year contract in the offseason to join the defending champions. He is averaging 4.8 points and 4.1 rebounds this season.
Gasol's absence could mean more playing time for center Damian Jones, who was recently signed to a 10-day contract and had eight points, three rebounds and two blocks in his debut with the team against Golden State.
Jones played just seven minutes against the Suns, his former team, and had four points, one rebound and a block.