Alan Knill, the Scunthorpe manager, said after the midweek friendly win over Middlesbrough that he expected the centre-back to be available for the first competitive game of the season.
He has not featured in any friendlies since the tour of Ireland, during which he fell and broke four bones.
"My hand is far worse than just a dislodged bone, four separate breaks that have needed wires and a plate to stablise," he wrote on his Twitter account.
"Chance I may miss some games. I know it is only my hand, but wires/plate beside tendons. Serious risk of losing use of it altogether. I don't miss games lightly, but I may have to."
Defender David Mirfin also missed the last game of pre-season against Middlesbrough on Wednesday night.
Knill said that was a precaution as he took a heavy knock to an ankle during Friday evening's 1-1 draw with a Manchester United XI.
United open the season on Tuesday night with a Capital One Cup first round trip to Derby County.
The details of Reid's injury appear to increase the chances of Tom Newey, currently on trial at the club, being given a short-term contract to provide cover.