Middlesbrough winger Stewart Downing was expected to hand in a written transfer request on Monday.
PA Sport understands the 24-year-old will ask to leave the Riverside Stadium following strong interest from Tottenham.
Boro chief executive Keith Lamb has already dismissed a bid - thought to be in the region of £6million - from the White Hart Lane outfit as "derisory", while manager Gareth Southgate has repeatedly insisted the England international is simply not for sale.
However, Downing's decision to submit a transfer request could force their hand with Southgate admitting when striker Ayegbeni Yakubu made it clear his future lay away from the Riverside Stadium that there was no point in hanging on to players who did not want to be there.
Southgate claimed Downing has remained unaffected by speculation over his future after his starring role in the FA Cup victory over Barrow.
The Boro boss said: "Stewart played in the middle of the park for us on Monday night (at Manchester United) and I think it has given him something else to focus on. It has given him a freshness and I think it gave us a bit more creativity."
Southgate is under no pressure to sell, although he had made no secret of the fact that he will have to raise his own funds if he wants to buy this month.
Boro value Downing at closer to the £15million mark but it remains to be seen whether or not Spurs, who have been admirers for several years, are prepared to go to anywhere near what would be a record transfer fee received by the Teessiders.
Southgate went on to reveal he is no fan of the transfer window, and it is no surprise given his lack of funds and the constant speculation over futures of the likes of Downing and Turkish striker Tuncay Sanli.
He added: "I think it's a bit of a nonsense the way it is. It's a distraction for the players - that's the issue. Agents are in the game to make money and they don't make money unless players sign new contracts or move."
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