Bennett was substituted at half-half in the 2-2 (then 0-0) draw with Barnsley at Oakwell last Monday night with a suspected broken thumb and early indications showed that he may require an operation.
However the club have now received the scans from an X-Ray and can reveal that whilst he severed a ligament damage, no bones were broken.
Blades boss Kevin Blackwell said: "He's severed the ligament. We are seeking a second opinion to see if there is a route to take without an operation."
Its unknown as to how long the keeper will be out of action with Mark Bunn (on loan from Blackburn Rovers) likely to re-take the number one spot.