Another day deep inside the hockey M*A*S*H unit known as the Bruins’ training facility in Brighton.

David Krejci and Jake DeBrusk, two of the club’s key forwards, did not participate in Tuesday’s practice and both will be hors de combat Wednesday for the 7:30 p.m. match with the Tampa Bay Lighting at the Garden.

According to coach Bruce Cassidy, DeBrusk sustained an upper-body injury in Sunday’s 4-2 loss to the Oilers, and Krejci aggravated an injury that recently had the talented pivot out of the lineup for 11 games.

No telling how soon either of the two forwards will return. Cassidy only categorized their status as day today.

With those two out of the mix: the lines shaped up like this for the 45-minute workout:

Brad Marchand-Patrice Bergeron-David Pastrnak.

Danton Heinen-Riley Nash-David Backes.

Frank Vatrano-Ryan Spooner-Noel Acciari.

Matt Beleskey-Sean Kuraly-Tim Schaller.

Marchand, the club’s top scorer last season, has missed the last six games due to injury. He made it through the entire workout, but his availability will not be assessed until prior to game time on Wednesday.

Backes, who had 10 inches of his colon surgically removed a month ago, again skated through the full workout and said he is inching closer to a return — though that’s not likely to be against Tampa.

“Feel pretty good,’’ said the veteran center/wing. “A little more contact today — trying to egg on a little more contact with the day off yesterday to try to really push and test things . . . everything went well, and we’ll see what tomorrow brings.’’

Not having a firm return date in mind, said Backes, has helped in his recovery. The original prognosis had the 33-year-old veteran workhorse out through most, if not all, of December.

“We haven’t had a big highlighter out,’’ he said, as if circling an imaginary date on the calendar. “We haven’t say, picked a day out before Christmas and tried to schedule everything for that. It’s been fluid. It’s been dynamic. We’ve progressed faster than we imagined going into the surgery — and if that date gets flexed around soon rather than later, great.’’

Backes said he is back eating his normal food selections with no dietary restrictions, despite having two acute bouts of painful diverticulitis, inflammation of the digestive tract, that prompted his surgery. His weight has dropped some 10 pounds.

“Maybe still being 10 pounds lighter I’ll get around a little bit better out there,’’ he mused, “and keep up with these kids a little better.’’

The MGH surgical staff, explained Backes, performed the operation with an arthroscope, which likely helped shorten his recovery period. He also did not require a temporary colostomy, the colon resectioned during a four-hour operation.

“I think my second day I got cream of wheat and toast,’’ he said. “I never thought cream of wheat and toast could taste so good.’’

Rask ‘not that far away’

Following the workout, Cassidy said he will not name his starting goalie against Tampa until Wednesday morning.

Tuukka Rask was in net for Sunday’s 4-2 loss to the Oilers, after Anton Khudobin started and won the previous four games.

“Ideally, I’d like both goalies to give us a chance to win every night and be on top of their game,’’ Cassidy said. “I think we have seen that with Anton now and Tuukka’s not there yet. We’ve got to find a way [to get him there]. At the start of the year, that’s what we said, we want both goalies to play well and give us a chance to win every night. So that hasn’t changed. Just maybe the script has been switched from what we thought.’’

Cassidy, generally pleased with Rask’s performance on Sunday, doesn’t believe the veteran stopper (now 3-8-2) is far off his A game.

“He just hasn’t pulled it all together yet,’’ Cassidy said. “That’s a product of the individual. That’s a product of how the team plays in front of him. If we can get both a little bit better, I think the result will be there. We are not that far away. I don’t believe that, anyway . . . you guys [media] will have your opinion, or the outside world, but we are not that far away.’’

Bjork back on ice

Rookie forward Anders Bjork, knocked out of the lineup Nov. 11 on a heavy hit to his head and neck by the Maple Leafs’ Matt Martin, was first on the ice — his first time on skates since his injury.

Bjork, a speedy right winger, wore a red sweater while on the ice, indicating he was not to engage in contact. Over the weekend, Cassidy said Bjork would not be available for games this week.

A lefthand-shot right winger, Bjork played in 16 games before being injured, and delivered a line of 3-6—9.

The Bruins have not disclosed the nature of his injury, although his time on the sideline could suggest that he was concussed. Martin spotted the rookie cruising through center ice with his head down and leveled him with a menacing hit.

Lightning strikes

Tampa Bay, first in the East with a 16-5-2 record, played in Buffalo Tuesday night, possibly tiring them out a little for the game here.

To underscore what a difference a healthy lineup makes: As of Tuesday morning, the Bolts had played 23 games, and 14 of their players suited up for all of them; the Bruins had played in 22 games and only seven had played in all of them.

Through Monday’s action, Tampa linemates Steve Stamkos (36 points) and Nikita Kucherov (34) were 1-2 in league scoring. Ex-BC Eagle Johnny Gaudreau, Calgary, also had 34 points.

How to defend Tampa’s Terrible Two?

“They’re a little bit more tic-tac-toe in the offensive zone,’’ Cassidy said. “They are less through the neutral zone with high-end speed. So for us, we have to find them in the offensive zone. They’re not center-lane drive, park in front . . . they find those [passing] seams. So we’ll have to have active sticks and scope out, I guess is what we’ll be telling our D. You can’t play in the blue paint, because these guys will throw it through seams and [make] off-net play. You have to scope out and find them.’’

Kevin Paul Dupont can be reached at kevin.dupont @globe.com. Follow him on Twitter @GlobeKPD.