The Republic of Ireland international was injured in a collision with Tigers goalkeeper Steve Harper during Tuesday night's defeat by Southampton.
Although scans revealed no break, there is serious ligament damage and manager Steve Bruce believes McShane is unlikely to be seen again until next term.
"We knew it was a serious one when we saw the pictures, his ankle was practically the other way around, so Paul has an operation on Monday," said Bruce.
"It's not broken but he's severed a couple of ligaments in there that need repaired.
"We don't know the real extent until the surgeon goes in but I wouldn't have thought he'll play any more part in this season.
"I would have thought it will be about six months out, so maybe the best case scenario is to be fit for the start of next season."
Hull's defensive resources are stretched somewhat at the moment, with McShane joining James Chester and Liam Rosenior on the sidelines ahead of Monday's FA Cup fifth-round clash at Brighton.
Chester and Rosenior are making good progress in their own rehabilitation and could be in contention for Hull's next Barclays Premier League clash at Cardiff.
Source : PA
Source: PA