The Ireland international withdrew before Munster’s draw away to Exeter last Saturday with a tight hamstring and he had a scan on the injury yesterday with a view to being ruled fit for selection against Gloucester in the next European tie, Saturday at Thomond Park.

“Keith is going to have a scan on the injury. He’s a worry,” said Van Grann.

Munster picked up some other injury concerns in the hard-fought draw with Exeter, with Sam Arnold getting treatment for a blow to the throat, while John Ryan twisted an ankle in Saturday’s game as well.

“Sam Arnold is back with a smile on his face, but he’ll see a specialist later this week,” said Van Graan.

“The other player’s boot got his throat, it’s a very sensitive part of the vocal chords, so we took him off straight away. He was discharged, he’s in good spirits.

“John Ryan rolled his ankle and is fifty-fifty - it’s the same ankle he rolled before.”

Long-term injury victim Conor Murray will not play against Gloucester while Alby Mathewson may train later in the week.

“He (Mathewson) tried his best to get on the pitch last week but he couldn’t,” said Van Graan.

“He had a pretty big blow to the knee so the medical staff will have a look at him tomorrow.”