Currently four points clear of the Blues, Munster know they have to take at least two points away with them to secure the final play-off spot.

The 22-year-old’s withdrawal adds to the long list of Munster injured which includes Mick O'Driscoll, Doug Howlett, Ian Dowling and talismanic leader Paul O'Connell.

Earls ,who was the only player to get a try in last week’s Heineken Cup semi-final defeat to Biarittz, would have played a crucial role in holding back an in-form Blues team.

The Blues have won six in a row and are pushing hard to make sure they come away with some silverware this season.

Lifeimi Mafi will move in to fill the hole left by Earls and Tom Gleeson will be called up to play on the wing.

Blues coach Dai Young knows even without key players Munster will not roll over easily.

"Munster will probably want to come away with something so they can get in the top four and give the Magners title a real challenge," said Young.

Young has picked a powerful team to do the job, with a back row combination of Xavier Rush, Martyn Williams and Maama Molitika looking to create havoc.

While Jamie Roberts and Leigh Halfpenny will hope to open up Munster’s defence.

Munster will rely on old heads Ronan O’Gara and returning Peter Stringer to control the game and keep them in the hunt for the Magners Title.