10 Dec, 12:23
Ireland's John Lacey will referee his first ever RBS 6 Nations match in February, while Alain Rolland is also included in the Elite Panel in what is his last season.
Both players sustained ankle injuries but Buckley's injury, which occurred during the 36-21 bonus point triumph at Clifton Lane, has proven the more serious and he has been ruled out of the return date with Rotherham.
That blow is softened by the fact that a trio of back rowers - Niall Ronan, Sean Dougall and Barry O'Mahony - all return to full training this week and will all therefore be in consideration for next weekend's matches.
Tommy O'Donnell, another member of the province's back row contingent, will also be reintegrated into squad training towards the end of this week. However, he is unlikely to be in contention for a place in either squad.
Ronan O'Gara is also reported to be showing no ill-effects from the back problem that made him doubtful for the round 3 encounter with Saracens last Saturday.
The injury arose after training last week and as a result young centre/out-half JJ Hanrahan was sent back from England as cover.
However, O'Gara, the Heineken Cup's record points scorer, pushed the issue to the back of his mind to play a key role in the 15-9 victory.
The Corkman kicked five penalties from five attempts to move his record tally onto 1318 points from 106 outings in the tournament.
Meanwhile, following the changes made to last week's refereeing schedule with Pascal Gauzere taking the place of the injured Romain Poite, fellow French referee Jerome Garces will now officiate next Sunday's Heineken Cup game between Saracens and Munster at Vicarage Road.
Garces was originally named as an assistant referee for the round 4 fixture with Gauzere at the helm, but they will now make the switch for the second of the back-to-back Anglo-Irish clashes.