Christian Pulisic has been sent for a scan after feeling his hamstring in the warm-up, which saw him taken out of the starting XI at Burnley.
It is a potentially significant blow to the Blues, with the 22-year-old having previously missed large chunks of the 2019-20 campaign with muscular issues.
Pulisic was also forced off in the FA Cup final against Arsenal after a hamstring injury.


Thankfully for Frank Lampard, Timo Werner replaced Pulisic in the team, and was among the scorers as Chelsea ran out 3-0 winners over Burnley at Turf Moor.