Albian Ajeti is open to leaving West Ham on loan for the rest of the season but is hamstrung by UEFA rules.
The 22-year-old, who is understood to be frustrated at a lack of first-team opportunities since signing from FC Basel in the summer, has already played competitive matches for two clubs this season.
That leaves his options for a potential loan switch in January drastically short - able only to join a team in a league starting a new season in the New Year such as Sweden, the USA or Japan.
A string of European clubs are understood to have made offers to take him on loan without realising it would not be possible to register him until the 2020-21 season.
Ajeti is yet to start a Premier League game for West Ham following an £8m move in August, making five sub appearances in the league and two starts in the Carabao Cup.