BOSTON -- Bruins general manager Peter Chiarelli’s job has become a lot more challenging.

With the team barely holding on to a playoff spot, the news that top-line center David Krejci will miss four to six weeks with a partially torn MCL in his left knee means Chiarelli needs to find a replacement before Monday’s NHL trade deadline.

Chiarelli already was in the market for a point-producing forward, but now he needs to figure out what to do without Krejci’s services.

When David Krejci missed 20 games earlier this season, the Bruins' offense often looked lost. Cal Sport Media/AP Images

If Krejci’s rehab goes according to plan and he’s able to return within six weeks, the Bruins will have only a few games remaining in the regular season. If the team’s current trend continues, it will be fighting for that postseason berth until the final game on April 11 against the Tampa Bay Lightning.

With the trade deadline less than a week away, the Bruins are dealing with more what-ifs and now-whats. Since there’s a possibility Krejci could miss the remainder of the regular season, the team could receive salary-cap relief if it placed Krejci on long-term injured reserve.

Krejci’s cap hit is $5.25 million and if he’s placed on LTIR, it would give Chiarelli more flexibility to acquire a player via the trade market before Monday’s deadline. Krejci still would be available for the playoffs if placed on LTIR.

The Bruins already recalled forward Ryan Spooner from Providence of the AHL for Sunday’s 6-2 win over the Chicago Blackhawks, but the speedy forward is not the answer. But Spooner playing with rookie David Pastrnak did open up some space, and that line, which also featured Milan Lucic, did create some offense.

Chiarelli needs to find a suitable and reliable centerman to fill the void until Krejci’s return.

But who is available?

The Bruins could pursue Arizona Coyotes veteran forward Antoine Vermette. There are limited options for the Bruins, and Chiarelli has lost a bit of leverage now because other GMs know he may be desperate.

If Chiarelli and coach Claude Julien believe Spooner could help out at center, maybe the Bruins decide to target Winnipeg Jets forward Michael Frolik. The 27-year-old winger will be an unrestricted free agent at the end of the season. Chiarelli would have to give up a lot to get Frolik for the short term, and it’s unlikely the Jets would consider such a move, given that they’re in the playoff picture in the Western Conference. It’s an interesting thought, though, and his current cap hit is $3.3 million.

Either way, Krejci’s absence will hurt. It’s horrible timing for the Bruins.

When Krejci missed 20 games earlier this season due to a groin injury, the Bruins posted an 8-9-3 record. During Krejci’s hiatus, Lucic was lost and the entire lineup struggled through numerous line combinations.

Chiarelli needs to decide whether he believes this team, as currently constituted, can earn a postseason berth and do some damage in the Stanley Cup playoffs, or if he needs some outside help. His answer should be the latter.