Horton has a severe concussion stemming from the brutal hit and will miss the rest of the playoffs, the team said Tuesday.
Rome was assessed a five-minute major and a game misconduct.
"Two factors were considered in reaching this decision," NHL senior vice president of hockey operations Mike Murphy said in a statement Tuesday. "The hit by Rome was clearly beyond what is acceptable in terms of how late it was delivered after Horton had released the puck and it caused a significant injury."
If the Stanley Cup finals end before Game 7, Rome's suspension will carry over to the start of the 2011-12 regular season.