Matheus Nunes went AWOL from Wolves training on Monday after seeing an offer from Manchester City rejected.
City bid 47m for the midfielder last week and saw it turned down.
Wolves are demanding 60m to sell the Portugal international and expect City to try again before Friday's deadline.
They now intend to fine Nunes after he refused to train yesterday.
Nunes joined Wolves a year ago from Sporting CP for 38m, signing a five-year contract.