While Nathan Horton's upper-body injury didn't look good when he left the game in the first overtime of Game 1 against the Blackhawks, it doesn't appear to be anything too serious.

It's believed to be a left shoulder issue for Horton, who was knocked out of Game 1's 4-3 triple-overtime loss after fighting Chicago defenseman Niklas Hjalmarsson for position.

Bruins coach Claude Julien termed Horton's injury as a "day-to-day" situation, and said the Bruins "have their fingers crossed" that he'll be able to return for Saturday night's Game 2 against the Blackhawks.

Horton had an assist in the Game 1 loss and leads the NHL playoff field with a plus-22 rating.

Clearly it would be a huge blow for the Bruins if the David Krejci/Milan Lucic/Horton line were forced to break up. They've been the NHL's best line during the playoffs, and have put up 21 goals and 56 points in 17 games while also dominating Game 1 against the Blackhawks.

If Horton can't answer the bell for Game 2, then it's likely that Tyler Seguin would be pushed up to the top line since he filled in at right wing for Horton during the overtime sessions.

Horton's injury is believed to be related to something he has been playing through during the playoffs.

He suffered a shoulder injury in a fight with Jarome Iginla on April 20 during Boston's final regular season game against the Penguins.