Marleau, 40, is the Sharks' franchise leader in games (1,551), goals (518) and points (1,102). He has 10 goals and 10 assists in 58 games this season.
"Patrick is one of the most iconic players to ever wear the Sharks uniform," Sharks GM Doug Wilson said in a statement. "Although we have had a disappointing season in San Jose, he deserves every opportunity to have a chance at winning a Stanley Cup, and we're happy to help accommodate that. We wish him the best of luck."