League sources told ESPN that Gasol's new three-year deal includes a partial guarantee in the third year of the pact.
The 37-year-old posted 12.4 points and 7.8 rebounds per game last season. Gasol played the first seven seasons of his career for the Memphis Grizzlies before being traded to the Los Angeles Lakers in 2008. He won back-to-back titles with the Lakers before signing with the Chicago Bulls in 2014.
The six-time All-Star opted out of a $16.2 million option for next season. The Spurs used that room in their salary cap to sign free agents Rudy Gay, Brandon Paul and Joffrey Lauvergne this offseason but are still working on a deal to bring back veteran Manu Ginobili.
"I want to play the maximum number of seasons, as long as I feel good," Gasol said earlier this offseason, according to NBC 4 San Antonio. "I have played 16-years in the NBA and I hope to play some more, but I have to keep working and respect any injuries, as I have so far."
Gasol came off of the bench last season behind Dewayne Dedmon, but still managed 25.4 minutes per game. He shot a career-best 53 percent from 3-point range.