A disappointed David Krejci limped through the Bruins’ locker room Tuesday morning, sporting a brace on his left knee. Boston’s top-line center is frustrated that he will be sidelined the next 4-6 weeks with a partially torn MCL, but he said he’s determined to return to the lineup before the end of the regular season and be a factor in the playoffs. He said he felt fortunate that he did not need surgery after suffering the injury during the second period of the Bruins’ 5-1 loss to the St. Louis Blues on Feb. 20, colliding with the Blues’ Alexander Steen. “I’m kind of relieved that I know that I’ll be back before the season is over,” Krejci said. “I’ll be doing everything I can every day to come back as fast as I can. “Once I come back, I don’t want to be the weak link. It’s all up to me how hard I’m going to work to get back.” Krejci hopes to return before the end of the regular season to prepare himself for the playoffs. A 6-week timetable would peg his return for sometime during the first week of April. The regular season ends April 11. The Bruins have not placed Krejci on long-term injured reserve, a move that would give general manager Peter Chiarelli more flexibility with the salary cap in order to make a trade before Monday’s deadline. It would also make Kreji ineligible to return until the playoffs. “This question is for management, but no, I don’t want to sit out. I want to play, obviously,” Krejci said. “If there’s only a little chance I can play, I would like to play. Management has to do whatever they feel is right for the team and get our team into the playoffs. It’s not an easy decision for them, but [Chiarelli’s] been making good decisions since I’ve been here, so I’m pretty sure he’s going to make the right one again.”