Donoghue suffered the injury in the third quarter of the Cardinals' 28-24 win over Cincinnati on Oct. 13.
After visiting with specialists in Indianapolis on Friday, it was diagnosed that Donoghue's spinal cord has tightened and there was no fluid in that region to protect the spinal cord from further injury.
"I feel for Mike a great deal," said head coach Steve Kragthorpe. "Mike was developing into a good football player, but he was also a tremendous person. We are disappointed he will no longer have the opportunity to play football at Louisville, but he will always be a member of the Cardinals' football family. Our thoughts and prayers are with Mike during this difficult time."
Donoghue started seven games at guard for the Cardinals this season.