Chelsea face a decision over what to do about Diego Moreira, who currently plays for sister club Strasbourg.
That is because Borussia Dortmund want the 21-year old left-sided Belgium player, but Chelsea retain a buyback option. The London club signed him from Benfica in 2023, and he made his debut in an EFL Cup tie against Wimbledon in August of that year.
However, almost immediately he was sent on a season long loan to Ligue 1 and Lyon, and although he was recalled after four months, he was subsequently sold to Strasbourg in a permanent deal.
There he played under Liam Rosenior, who oversaw his transition from a winger to a more defensively-minded left back.
Although he has dual Belgian and Portuguese citizenship, he has chosen to play his international football for Belgium, and has two senior international caps with them.
If they do sign him back from Strasbourg, he will be the latest example of players moving between the two clubs.