Chelsea will have to pay Manchester United a fee of £5 million ($6.5m) if they back out of the deal to sign Jadon Sancho permanently this summer, a source has told ESPN.
Sancho is on loan at Stamford Bridge. Chelsea have an obligation to make the move permanent for a fee of £25m if they finish higher than 14th in the Premier League.
Chelsea are fourth in the table with nine games to go, meaning the condition is likely to be met. However, there is a clause in the agreement with United which would allow Chelsea to send Sancho back to Old Trafford if they pay a penalty of £5m.
Sources close to Chelsea have played down the possibility that Sancho could return to United.
However, the 24-year-old has been in and out of Enzo Maresca's team so far this season, scoring twice in 28 appearances.
Sancho hasn't found the net since the 4-3 win over Tottenham in December. Sources close to United have told ESPN they are relaxed about the situation.
Sancho's return would give the club a headache while they also try to offload Antony and Marcus Rashford.
Like Sancho, both Antony and Rashford are both currently on loan at Real Betis and Aston Villa, respectively.
Head coach Ruben Amorim sanctioned the departures of both Antony and Rashford in January. He's not yet worked with Sancho, who left before the 40-year-old's arrival to replace Erik ten Hag in November.
A source has told ESPN that Amorim will get the final say on Sancho's future if the winger returns, but that the most likely scenario remains a permanent exit in the summer.
Information from ESPN's James Olley contributed to this report.