Photo: Bridget Samuels/Ikeastan Hockey

The Bruins escaped the inevitable injury bug for the first six games of the 2010-11 NHL season, but last night, it eventually caught-up with them.

Today, the B’s have announced that 26-year-old defenseman Johnny Boychuk will be sidelined for appoximately four-weeks with a slight fracture to his left ulna — one of the two long bones in the forearm, on the outside/pinky-side of the arm. That would put Boychuk’s early estimated return somewhere around Nov. 20, when the B’s host the LA Kings, or the 22nd when Boston travels to Tampa Bay if all goes according to plan.

Boychuk was slashed by New York Rangers forward Brandon Dubinsky just 5:34 in the first period of Saturday night’s 3-2 loss to the Blueshirts. The 6-foot-2 Boychuk came back to finish the first period with 07:28 time on ice, one shot on goal, one hit and one blocked shot, then did not return for after the first 20 minutes of action.

With No. 55 on the sidelines for the next few weeks, anticipate Adam McQuaid to fill-in for the time being.

Boychuk posted 0-3-3 totals in six games for the Bruins this season, while logging just over 20 minutes per game, 12 shots on goal, 11 blocked shots, and seven hits.