On Jan. 7, after the Blackhawks pumped four goals past Tim Thomas, Bruins coach Claude Julien pulled the starter and replaced him with Rask. On Jan. 18, Julien tapped Rask once more after Ottawa tucked three pucks behind Thomas on nine shots. Just two games later, the goalies crossed paths on the RBC Center ice when Julien sent Rask in for relief following four Carolina goals on Thomas.

“You try to be as ready as possible no matter what,’’ Rask said. “When it happens, you go in there, try not to think too much, and do your job. But it’s never easy.’’

This season, Rask has relieved Thomas four times. Thomas was pulled only once last season, in favor of Manny Fernandez. As stinging as the calls to the bench have been for Thomas, it’s just as taxing on the rookie goalie to enter cold and try to turn his team around (the Bruins lost all four times the midgame change has taken place).

“You’re just sitting there for a period or two, pretty much doing nothing,’’ Rask said. “I think that’s the hardest thing.’’

On Friday, the Bruins most likely will look to Rask to stop their 1-7-1 freefall out of the Eastern Conference playoff chase. Rask has started and won both of the Bruins’ games against Buffalo this season, posting a 2-0-0 record with a 1.50 goals-against average and a .946 save percentage against the Northeast Division leaders. Rask has won all four games he has started against Northeast opponents (two wins over Toronto, too).

Rask’s second win over the Sabres (Patrice Bergeron beat Ryan Miller in overtime to give the Bruins a 2-1 victory) took place within the 22-year-old’s longest starting streak of the season. With Thomas nursing a hand injury, Rask made six straight starts between Nov. 16-27. After dropping a 4-1 decision to the Islanders, Rask and the Bruins rattled off four straight victories (all on the road), their longest winning streak of the season. Two of the wins came in the shootout and one in overtime.

Since then, Rask has started consecutive games only once (back-to-back wins over the Maple Leafs in early December). Rask has lost his last three starts; his most recent win was Dec. 30 when he posted a 4-0 shutout over Atlanta.

“Of course it helps when you’re playing every day and you’re winning,’’ said Rask (10-6-2, 2.14 GAA, .925 save percentage). “But as a goalie, you try not to get too high or too low. You just try to keep your focus at the same level, no matter what. Every day, you think right and try to do your job.’’

“Nothing too big,’’ Begin said of his injury. “We’re coming along. Hopefully I’ll be ready for this weekend.’’

Begin (3-9 -12), who last centered Bitz and Milan Lucic on the third line, hadn’t missed a game all season before the injury. If Begin can play against Buffalo Friday or against the Kings Saturday, Trent Whitfield most likely would be the spare forward.

“I know we’ve got all the elements to be better than that,’’ said Begin. “We have to be more focused and play within the system. If we do that, we’ll win games.

“There’s still a lot of games left to play. I’m not worried. We know what we have to do. If we do it well, we’ll get ourselves in a better position. It’s coming. We know we had a tough last month. A lot of injuries doesn’t help. The team’s going to get healthy and we know we’re going to be better.’’

Fluto Shinzawa can be reached at fshinzawa@globe.com.