Mick O'Driscoll will replace Paul O'Connell in the Munster second row for Saturday's Heineken Cup clash in France against Perpignan.
The Ireland A lock was not even in the Munster squad for last week's Celtic League semi-final victory over Ulster but with O'Connell suffering a broken thumb in that game, O'Driscoll has leapfrogged veteran Mick Galwey to win a starting place this weekend.
Munster coach Alan Gaffney said: "Paul is a class player and a big loss but then again when you've got Gaillimh and Mick O'Driscoll on the bench things aren't too bad.
"It's a blow but Mick's been given another chance. He suffered from being left out of the 22 last week and I'm sure he'll stand up this week and show us what he's made of.
"We pick a side depending on who we're playing and who we think is best suited for it. This week we believe we need a lineout that's going to be particularly effective and Mick probably steps up over Gaillimh in that regard.
"He's probably more athletic in the air whereas Gaillimh's very strong in other parts. This week, Mick's probably the better option."
The only other change to the Munster side is also enforced, with Mossie Lawlor replacing hamstring victim Anthony Horgan on the left wing.
Colm McMahon replaces Lawlor on the bench where Gaffney will choose between Denis Leamy and former London Irish player Eddie Halvey for the back row vacancy tomorrow.