The San Jose Sharks forward added that he isn't just thinking about one additional season and could perhaps play more as long as he feels good.
"Thinking I got five more years left in me," he told TSN's Pierre LeBrun via text message.
Thornton was undecided on whether he'd return for another campaign after the Sharks were eliminated from the playoffs in May. He did say, however, that if he returned it would be to San Jose.
"It is safe to say I'm a Shark," he said at the time. "There's one team and it's here."
Thornton remained productive in his age-39 season. The future Hall of Famer tallied 51 points in 73 regular-season games and added 10 points in 19 postseason contests - all while playing predominately in a third-line role.