Pro14: Leinster v Ulster (Sat)
|Guinness Pro14 - Leinster v Ulster|
|Venue: RDS, Dublin Date: Saturday, 6 January Kick-off: 17:35 GMT|
|Coverage: Live on BBC2 NI and the BBC Sport website|
Leinster have ruled out Rory O'Loughlin, Richardt Strauss, James Ryan and Sean O'Brien for the Pro14 derby against Ulster in Dublin.
O'Loughlin misses out because of a head injury while hooker Strauss is sidelined with a back injury.
Lock Ryan has an ankle problem and back-row O'Brien in unavailable due to tightness in his hip.
Leinster beat Connacht on Monday to earn a fourth league win in a row while Ulster fought back to defeat Munster.
Ulster lie third in Conference B and six points behind second-placed Leinster.
O'Loughlin had a Head Injury Assessment at full-time after an incident in the last play of the 21-18 win over Connacht and the centre has entered the Return to Play Protocols.
Strauss and Ryan picked up their injuries in the Boxing Day victory over Munster while Leinster hope Lions and Ireland flanker O'Brien will return for the final two Champions Cup games.
Scrum-half Luke McGrath passed his Head Injury Assessment after the Connacht and is available along with Adam Byrne, who has recovered from a knee injury.
Jack McGrath could get a front-row start after coming through the Return to Play Protocols but flanker Dan Leavy is rated doubtful because of a back injury.