Munster head coach Anthony Foley makes four changes to the side that defeated Zebre for this Sunday's Guinness Pro12 Round 14 clash against Ospreys at Musgrave Park.

Three of those changes are seen in the pack with Dave Kilcoyne and Mike Sherry returning to the front row alongside John Ryan who remains at tighthead.

There is no change in the second row with Dave Foley again partnering Mark Chisholm while Dave O'Callaghan makes his first start since returning from an adductor injury at openside. 

Billy Holland remains as captain and blindside flanker with Jack O'Donoghue making the positional switch to number 8 for the first time this season.

The only change across the backline comes at scrum half with Duncan Williams returning to partner Ian Keatley in the half-backs.

Rory Scannell and Francis Saili form the centre partnership for the seventh consecutive game with wingers Ronan O'Mahony and Darren Sweetnam and full-back Andrew Conway all retaining their starting positions.

Munster: Andrew Conway; Darren Sweetnam, Francis Saili, Rory Scannell, Ronan O'Mahony; Ian Keatley, Duncan Williams; Dave Kilcoyne, Mike Sherry, John Ryan; Dave Foley, Mark Chisholm; Billy Holland – capt., Dave O'Callaghan, Jack O'Donoghue.

Callum Black will make his 100th appearance for Ulster when they take on reigning Guinness PRO12 champions, Glasgow Warriors on Friday.

The loosehead prop joined Ulster from Worcester in 2011 and has racked up 99 appearances to date, including 13 this season.

Sam Windsor will make his competitive debut for Ulster after being selected at outhalf by Director of Rugby, Les Kiss. The 28-year-old replaces Ian Humphreys, who suffered a concussion in the 17-15 win over Newport Gwent Dragons last weekend.

Stuart McCloskey will start in midfield alongside Darren Cave, facilitating Stuart Olding's switch to fullback. Jacob Stockdale and Craig Gilroy will line out on the wings, with Ruan Pienaar continuing at scrumhalf.

The front row of Black, captain Rob Herring and Ricky Lutton remains unchanged from the Dragons encounter. Franco van der Merwe returns to the team after a well-earned rest last week; he will partner Alan O'Connor in the second row.

Chris Henry, who has not featured for Ulster since picking up a shoulder injury in December, has returned to the fray and has been included among the replacements.

Ulster: S Olding, C Gilroy, D Cave, S McCloskey, J Stockdale, S Windsor, R Pienaar; C Black, R Herring, R Lutton, A O'Connor, F van der Merwe, R Diack, S Reidy, N Williams;

Cian Healy and Mike Ross both start for Leinster in their Pro12 clash with Zebre at the RDS on Friday evening.

There are five changes to the team that lost out to the Dragons last time out with three in the pack and two in the backs.

Healy and Ross return from hamstring and knee injuries respectively to prop down alongside James Tracy, with Ross Molony and Hayden Triggs continuing in the second row. 

The back row sees Josh van der Flier return from Ireland camp at open side flanker with Dominic Ryan and Jordi Murphy again selected at blind side and number eight. 

In the backs Isa Nacewa returns from a knee injury to captain the side form the left wing with Adam Byrne again starting on the right and Zane Kirchner selected at full back.

Ben Te'o and Garry Ringrose continue in midfield with Isaac Boss partnering Cathal Marsh in the half backs. 

Leinster: Zane Kirchner, Adam Byrne, Garry Ringrose, Ben Te'o, Isa Nacewa, Cathal Marsh, Isaac Boss, Cian Healy, James Tracy, Mike Ross, Ross Molony, Hayden Triggs, Dominic Ryan, Josh van der Flier, Jordi Murphy