It won’t be easy for the Bruins, but they’ve been forced to live without Patrice Bergeron before. Given that his latest concussion is the fourth of his nine-year NHL career and that he missed nearly the entire 2007-08 season after getting severely concussed, the Bruins unfortunately know what it takes to win with No. 37 out of the lineup. At least things sound positive at this point in terms of Bergeron’s attitude and optimism less than 48 hours removed from his latest head injury. “He sounded positive and sounded good. You never know with these things. We have said things before and guys have taken a step back, and some guys have progressed quicker than others,” said Claude Julien. “It’s really a tough thing to predict as far as ‘Is he getting that much better?’ He could have a setback tomorrow. We just don’t know.” They had to scrape and claw that season to eke into the playoffs as the No. 8 seed, and they’ve filled in the blanks in the last couple of instances. The Bruins obviously hope that the latest “moderate concussion” is similar to the one that only sidelined him for two playoff games two years, but the truth is that recovery from head injuries is truly unknown. With that in mind the Bruins have taken a leap of faith and slotted 21-year-old Tyler Seguin into Bergeron’s center position -- the position for which he was drafted No. 2 overall three years ago, overstocking Boston with quality down the middle. Now Seguin gets his shot with Jaromir Jagr and Brad Marchand as his wings, and Claude Julien thinks he’s ready to handle the responsibility. He probably won't be winning 61.5 percent of his face-offs or playing Selke Trophy level defense like Bergeron, but then again Bergeron's only peers in the NHL are guys like Jonathan Toews, Pavel Datsyuk and David Backes. So expectations should be realistic for Seguin's first big shot in the middle.