Steven Fletcher has demanded a transfer from Wolves.
Sunderland have had a couple of bids rejected this month and this has now prompted Fletcher to make his decision - which he revealed via his Twitter account.
"Just handed in a transfer request just to let the fans know where I am at right now," he wrote.
Wolves confirmed they had received Fletcher's request saying they will not let him leave until their valuation is met.
Their statement read: "Wolves can confirm that Steven Fletcher has handed in an official transfer request.
"The player's frustration stems from the fact that several bids have been rejected for his services, none of which meets the club's valuation.
"As previously stated, no player will leave Wolves unless the club's valuation is met.
"Wolves will be making no further comment at this time. "