UPDATE (6:41 p.m. ET): Following an ankle injury sustained in Game 4, Torey Krug will be out for the remainder of the Boston Bruins’ second-round Stanley Cup playoff series with the Tampa Bay Lightning.

ORIGINAL STORY: The Boston Bruins face an uphill battle in continuing their postseason run, and now, it appears that climb has become even steeper.

The Bruins will be without defenseman Torey Krug for Sunday night’s must-win Game 5 in Tampa Bay against the Lightning due to an ankle injury. If Boston is able to extend the series, it likely will have to do so without Krug moving forward.

Krug sustained the injury in Friday night’s Game 4, which the Lightning claimed 4-3 in overtime. Late in the third period, Krug awkwardly slammed into the boards after chasing down a puck alongside Tampa Bay winger Alex Killorn. The blueliner exited the game after the hit and later left TD Garden in a walking boot.

With Krug now unavailable for Game 5, the Bruins will turn to Nick Holden to fill the void. Holden has appeared in one game for the Bruins in these Stanley Cup playoffs, tallying an assist in 12:25 of ice time in Boston’s first-round Game 3 loss to the Toronto Maple Leafs.

Krug’s injury tacks on to Boston’s highly frustrating second-round series against Tampa Bay, which will come to a close if the Bolts take down the B’s on Monday night at Amalie Arena.

Thumbnail photo via Kevin Hoffman/USA TODAY Sports