He has needed two operations to cure a dislocated shoulder. The Scunthorpe Telegraph claim he is a target for the United manager Nigel Adkins.
"Obviously the challenge of missing so much of the past two years is hard, but he is a talented player and there might be an opportunity to bring him in from a pre-season point of view," said Adkins.
Watt began his career at Chelsea, but only made one senior appearance for the Blues - ironically in their 3-1 FA Cup third round win over Scunthorpe in January 2005.
United are also believed to be among the front-runners to sign the Morecambe winger Garry Thompson.