The Republic of Ireland frontman 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 that Kevin has torn his medial collateral ligament."
He added: "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."
Defender Christophe Berra admitted the loss of Doyle is a blow to his side's survival bid, but is confident they have the strength in depth to cover for the 27-year-old. Doyle has scored eight goals in all competitions this season, making him Wolves' leading scorer despite generally being required to lead the line on his own.
Berra said: "It's a massive blow for us, he's a top player, he does a great job for us up front. But we've got good strikers on the bench in Sylvan Ebanks-Blake and Steven Fletcher, who have come in this season and done well and scored goals for us. So we won't be getting down about that, we'll move on."
Ebanks-Blake has scored six Barclays Premier League goals this campaign - one more than Doyle, whose tally is boosted by three in cup competition - while five of Fletcher's seven goals have come in the league. Wolves are currently 18th in the table with 32 points, just one goal from safety.
They travel to Newcastle on Saturday looking to climb out of the bottom three in what is one of the tightest relegation battles in Premier League history.
Berra said: "I think it's two points between six or eight teams and we've actually got better points this season than at the same point last season, so it shows our improvement.
"We're a better team now, we play better football overall. As players, as individuals, we've improved so we'll go onwards and upwards. We're four games unbeaten and we'll be going away to Newcastle in high spirits."
Source: PA
Source: PA