The Republic of Ireland international suffered the injury during his country's win over Macedonia on Saturday and has returned to the midlands for treatment.
The club have not given up hope of Doyle featuring again this season but the head of their medical department, Steve Kemp, told the club website: "The scan has confirmed Kevin has torn his medial collateral ligament.
"We will be working with Kevin to get him back as quickly as the injury allows but the likely time span is anywhere between four and eight weeks."
Source: PA
Source: PA