Following an initial scan, the 23-year-old forward is now facing surgery.
But Wolves are as yet reluctant to give a likely comeback date.
“Michal sustained a significant multi-ligament knee injury,” said Wolves head of medical Phil Hayward. “He will see a consultant this week and undergo surgery once the swelling has subsided at some point in the next two weeks.
“He is expected to be out for a considerable time. The timeframe will become more apparent following surgery.”
Wolves’ busy treatment room
Zyro’s injury makes him the third Wolves player to suffer a serious knee injury this season.
Wolves have also lost winger Razak Boukari and defender Ethan Ebanks-Landell for the season, while centre-half Mike Williamson (thigh injury) has not figured since returning to the club from Newcastle United in January.
Since Christmas, they have also spent long spells without Zyro, who missed two months with a calf injury, James Henry, Dave Edwards and Jed Wallace.