Tom Orsborn of the San Antonio Express-News reported the veteran frontcourt player's likely offseason plans Tuesday.
Lee signed a two-year contract with the Spurs last August to provide depth on the interior.
Last season, the 34-year-old University of Florida product averaged 7.3 points, 5.6 rebounds and 1.6 assists while shooting 59 percent from the field across 79 games, including 10 starts.
Most impressive was his improvement at the defensive end. The inability to win one-on-one battles at that end of the floor has long been an issue for the 2005 first-round pick, but he ranked 21st among power forwards with a plus-1.5 defensive real plus-minus rating in 2016-17, per ESPN.com.
In April, Jeff McDonald of the San Antonio Express-News noted Lee talked about going with the flow under head coach Gregg Popovich.
"I don't pretend to have it all figured out, but that's why he's won five championships," he said. "No matter what he's doing, it's proven that he gets the job done. We've had a very successful year doing things his way, and he's had about 25 successful years doing things his way here. It's not up to us to ask questions. He puts us in the best possible position to win games, so we all say, 'Yes sir,' and do our best when we go out there."
It's unclear whether there will be mutual interest between Lee, who's recovering from a knee injury, and the Spurs for a potential reunion once he hits the open market.