Speaking to the Official Club Website, Town manager Joe Royle confirmed: "Alan will have a scan today and we will know more after that. If he has torn the hamstring it could mean him being out for up to six weeks."
"It will be a big blow for us if he is out for a while because the lad has come in and done a great job for us. He has become an integral part of the side but if he is missing, we will have to cope with that."
Should the results of the scan be as bad or worse than expected, despite Mahon being out for some time, it's likely that he will stay at Portman Road rather than going back to Blackburn, as the agreement is for Mahon to stay at Portman Road both in sickness and in health.
Another worry is over Skipper Jim Magilton, who came off at half time on Saturday, and is a doubt for tommorow nights game away at Crystal Palace as he is suffering with a calf injury.
Speaking of the doubts of his skipper, Town manager Joe Royle commented: "Jim's calf is full of fluid from the knock he took against Burnley and he was a doubt for the Stoke game right up to kick-off,"
"We will have to see how he is after today but he is a worry for the Palace match."