Team personnel said that the Grizzlies medical staff would evaluate the injury on Saturday. The Memphis Commercial-Appeal reported Gasol would have an MRI.
"Praying, praying," Grizzlies forward Zach Randolph said, according to Reuters. "Need him."
Gasol grabbed his knee while under the Spurs basket with 10:24 left in the second period and San Antonio leading 30-23. He never went down, but went straight to the Memphis locker room. He did not return to the bench before halftime, when Memphis announced the injury.
Gasol had two points on 1-of-3 shooting.
Kosta Koufos replaced Gasol, scoring six points and grabbing seven rebounds in 28 minutes.
"I just want Marc to be healthy," Koufos said, according to Reuters. "(But) I'm prepared for whatever obstacle."
Information from The Associated Press was used in this report.