Ian Maatsen's decision over a new contract could have a bearing on Marc Cucurella's departure from Stamford Bridge.
Cucurella is available for loan and Manchester United made enquiries on Saturday but Chelsea may not be so sure if Holland U21 international left-back Maatsen doesn't commit to a new deal.
The 21-year-old has been offered a lengthy deal but is unsure over the terms and the validity of signing it.
Burnley, Borussia Dortmund and West Ham are all keen on Maatsen and could match or offer better terms too.