Maple Leafs star center Auston Matthews, who has been dealing with concussion symptoms after colliding with a teammate in a game earlier this month, participated in his first practice in two weeks on Friday.

Matthews, who has missed six games, confirmed the nature of his latest injury Friday.

Lightning right wing Ryan Callahan is out indefinitely after taking a nasty spill into the boards in Thursday night's 4-1 win over the Coyotes, the team announced Friday.

Callahan, whose right arm was in a sling after the game, will be re-evaluated in three to four weeks with what the Lightning are calling an upper-body injury.