"He will have an ultrasound scan today and an MRI scan tomorrow, after which we will know more with regard to diagnosis and prognosis."
The Rodney Parade victory has Ulster through to the knockout stages of the Magners League, following on from their recent quarter-final appearance in the Heineken Cup.
They face an in-form Leinster side in a mouth-watering league semi-final at the RDS on Friday night
The province are already without the services of Stephen Ferris (knee), Paddy Wallace (thumb), Andrew Trimble (thumb) and Willie Faloon (shoulder), while South African prop BJ Botha also missed the trip to Newport with a knee injury.
The statement continued: "Stephen Ferris, who has been out since January with a knee injury, continues his rehab and in conjunction with his surgeons and the IRFU medical team. It has been decided that Stephen will not play again this season.
"Willie Faloon, who is currently unavailable having injured his shoulder in training two weeks ago, will undergo surgery this Thursday to repair a torn rotator cuff."
Commenting on Ulster's progress through to the semi-final stage, head coach Brian McLaughlin said: "We're delighted with where we are, we have backed up what we've done in Europe.
"We said we wanted to be in the top four and it's great to be here. We now have the bonus of going back to Dublin to play Leinster. That will be exceptionally tough.
"We've been there already but didn't play as well as we could have. So we have to go down there all guns blazing and give it a real crack. We want to go down there and do ourselves justice."