Booth exited Wednesday's game against the Kings in the third period after taking an inadvertent elbow to the head, the Associated Press reports. Booth previously missed 54 games during the 2009-10 on account of a pair of concussions, so the Leafs' training staff will surely tread carefully here. Coach Peter Horachek provided no update on Booth after the game, but it wouldn't be a surprise if the team called up an extra forward to cover for his potential absence for Thursday's game against the Sharks.