Sunderland midfielder Jack Colback has opted against extending his contract on Wearside, according to the Press Association.
It is reported by the news agency that Sunderland will now listen to offers for academy graduate Colback.
It had been suggested Colback would remain at the club following the news that manager Paolo Di Canio is open to selling Lee Cattermole during the transfer window.
The midfielder has 12 months remaining on his current terms, meaning a fee will be sought this summer as he will be able to leave for free next year.
Colback, 23, made 30 Premier League starts for Sunderland last season, but was at times played out of position at full-back.