Paterson, 33, fractured his fibula in innocuous fashion during Tuesday night's 1-0 pre-season friendly victory at Blue Square Bet Premier side Hereford.
Rovers initially hoped Paterson would only be out for a short period but he will now be looking to return to action at the end of August.
A statement on the club's official website read: "(The) news comes as a big disappointment to the Scottish defender, and the club, and we wish him well for a speedy recovery."
- Sports & Recreation
- Blue Square Bet Premier