Ulster centre, Paddy Wallace, is struggling to be fit for Friday night’s visit of Italian side, Zebre as the Province seek to get back on track after last week’s disappointing home loss to Ospreys.
Wallace suffered a leg injury against the Welsh side and underwent a scan on Monday.
The influential centre is likely to be named on Tuesday’s provisional panel but was said to be ‘50-50’ to be involved against bottom of the table Zebre.
Scrumhalf Ruan Pienaar is also expected to be named in the provisional panel. He suffered a stinger-type injury to the shoulder, but a scan on Monday was returned clear.
Outhalf, Paddy Jackson, who continues to shake off an ankle knock sustained while playing with the Irish Wolfhounds against England Saxons could be involved, but much will depend on the Irish injuries situation and if Declan Kidney required the young starlet for the match against Scotland in two weeks.
There was also mixed news for Ulster backrow, Sean Doyle.
Along with Neil McComb and Lewis Stevenson, Doyle agreed a new extension to his contract.
The 23-year-old Australian born open-side joined Ulster this year but had limited time after suffering a non-displaced fracture playing with Dungannon in an All Ireland League game at the start of the season.
While he was due to return shortly to playing again, Doyle has suffered a setback, requiring a plate in the leg which has ruled him out for the remainder of the season.
Stevenson’s deal will keep him with Ulster until June 2016, while McComb’s extension will keep him with the Province until June 2015.
Doyle’s is a one year extension until the end of the 2014 season.
Ulster Director of Rugby, David Humphreys, said: “Lewis and Neil have been important to us all season, while Sean showed in his first few games what an exciting prospect he is.
“I have no doubt that they will only get better as players and that is good for Ulster Rugby.”