Booth, who missed 45 games this season with a concussion, was crossing the Montreal blue-line with his head down when Spacek stepped into him with a shoulder. The Panthers forward lay on the ice for several minutes and looked wobbly as he was escorted off the ice by trainers.
Panthers officials described Booth's condition as alert and coherent before being taken to hospital. Booth was released from hospital on Friday and is expected to return to Florida to undergo further evaluation by the Panthers' medical staff.
Booth's injury from a blindside hit by Philadelphia's Mike Richards on Oct. 24 sparked a debate over headshots that eventually prompted the league to bring in stiff penalties for lateral or from-behind hits to the head for the rest of this season and the playoffs.
The hit by Spacek, who was not penalized on the play, was from the front.