Thornton, who had 10 points in 19 games this postseason, can become an unrestricted free agent July 1.
He is one of several players on the Sharks who face an uncertain future, and it is highly unlikely the 2019-20 roster will have the same personnel.
"You play with guys for eight months. Every day you got a schedule, you come to the rink, you see the guys, go on the road and then it comes to an abrupt end," forward Logan Couture said. "You don't know what to do with yourself. Then changes are made. Some of the guys you may not see until you play them the next season.
"It's the worst part of playing in this league. There are many positives, that's probably the biggest negative. But we expect there are going to be changes, and right now it's just too early to think about it."
Thornton could easily be among the changes, although there is still life left in his legs and magic in his hands. He had 51 points (16 goals, 35 assists) in 73 regular-season games, his highest point total in three seasons, and has 1,478 points (413 goals, 1,065 assists) in 1,566 games in 21 NHL seasons.
If he is not back, he will walk away from the team and city he has called home since being acquired in a trade from the Bruins on Nov. 30, 2005.
San Jose is where he grew from a confused young man trying to carry the burden of being the No. 1 pick in the 1997 NHL Draft into an undeniable star.
And if he walks away, either as a free agent or through retirement, there will be regrets about how it all ended here Tuesday.
"Well, you know, he's the face, he's the heartbeat of the organization," said Peter DeBoer, who has coached Thornton for the past four seasons. "What do you say? I think, like all the players in that room, as coaches we're disappointed for not helping him get there because he gives you everything he's got and should be there.
"So, you know, it's hard not to feel responsibility as one of the people around him for not helping him get where he belongs. He belongs playing for a Stanley Cup."
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