Leinster back row Jack Conan will be out of action for up to 10 weeks after sustaining a broken foot in a "freak" training accident.
"It was a freak thing," Leinster head coach Leo Cullen told RTÉ Sport. "His boot got caught in the ground and he's managed to break his foot.
"He'll have a procedure done next week so he'll be out for probably six to 10 weeks."
Sean O'Brien, Richardt Strauss and Mike McCarthy are unlikely to feature for Leinster in their European Champions Cup game against Bath at The Rec on Saturday.
All three picked up head knocks in the defeat to Wasps at the RDS last Sunday and, given the tight time-frame between games they are unlikely to be risked this week.
Rob Kearney, Ben T'eo, Luke Fitzgerald and Isa Nacewa trained today, however, and provided there are no adverse reactions, all four could feature on Saturday. The team will be named at noon on Friday.
Cullen is hoping for a reaction against Bath after the shock 33-6 drubbing to Wasps but knows his side face a tough task.
"It has been a challenge. It's just trying to get the game out of your system as quick as you possibly can, which is easier said than done when you lose 33-6 at home," he said.
"I didn't think the score really reflected the game. We gave away three pretty cheap tries.
"We had a lot of possession but didn't really utilise it as well as we could have.
"I didn't think the score really reflected the game. We gave away three pretty cheap tries"
"Wasps defended very well and made life difficult for us at the breakdown and it's not going to get much easier against Bath this week.
"They have a lot of good players across the board and a good coach. We had a very tough battle against them last year in the quarter-finals at the Aviva so we know it's going to be a very tough challenge."
In a pool that also features European champions Toulon, Cullen is well aware that Leinster have no further room for error.
"We've certainly made life very difficult for ourselves," said the former second row.
"It's an incredibly tough pool and losing a game at home makes life very difficult.
"So we need to make sure we get as much as we possibly can out of this game and we can't really think much beyond that."
