SAN JOSE -- As one center returned to practice on Tuesday, the Sharks could be without another.

On the same day top center Joe Thornton practiced for the first time since experiencing swelling in his surgically repaired right knee, second-line pivot Logan Couture collided with center Rourke Chartier in a three-on-three drill at the end of practice, and appeared to be grabbing one of his wrists.

San Jose head coach Peter DeBoer told reporters after practice he had yet to hear about the seriousness

"I don't have an update yet," DeBoer said. "I hope it’s nothing serious, but I don’t have an update.”

Couture has played in each of the Sharks' six games so far. He leads all San Jose forwards in average ice time (20:03), and has scored three points so far this season. The 29-year-old signed an eight-year contract extension with the Sharks on July 1, and led the team with a career-high 34 goals last season, playing in all but four regular-season games.

Prior to Tuesday's practice, the Sharks recalled center Dylan Gambrell from the AHL's San Jose Barracuda. Gambrell skated on the wing of Couture's line, while wingers Tomas Hertl and Kevin Labanc sat for maintenance days.