Ulster's Tommy Bowe has been ruled out for between four to six weeks with a groin muscle tear.
Bowe suffered the injury while on international duty with Ireland and the full extent of the damage was revealed in a scan today.
In other Ulster news ahead of their Heineken Cup clash with Treviso, Rob Herring sustained a stinger in the win over Zebre at the weekend. He returned to limited training yesterday and is expected to fully reintegrate later this week.
Backrow forward Mike McComish sustained a direct blow to his hip joint on Saturday. He trained today.
Paddy Wallace has returned to full training following the ACL injury that he sustained in February. He will be available for selection this weekend.
Captain Johann Muller has returned to training and will be available for selection this weekend.
Jared Payne continues his recovery from a groin injury. He will be assessed later in the week with a view to his participation against Treviso.
Scumhalf Ian Porter has returned to training this week and it is hoped that he will be available for selection at the weekend.
Prop Paddy McAllister re-aggravated a hamstring injury playing for his club at the weekend. A scan yesterday revealed that he sustained a small tear. He will be out of rugby for between four and six weeks.