Frank Lampard has revealed that Christian Pulisic has suffered a hamstring injury that forced him out of the win over Burnley, which saw Timo Werner start on the right-wing in the 3-0 win.
The German scored the third, after goals from Hakim Ziyech and Kurt Zouma as Chelsea ran out comfortable winners over Sean Dyche's side, to take them to the top four.
Lampard, speaking after the match, said they would wait for a scan before determining the extent of the injury.
"He had a small sensation in his hamstring," he said.
"We had to pull him and he couldn't play the game when he got that as part of the warm-up.
"We will have to scan it, it is frustrating. He has got fit, played three games and we rested him in the week and he came on and scores.
"He is so keen to do well for us but we will have to scan it and see how it is, I can't give you a timescale."
Burnley now move to the bottom of the table with one point after 6 games, while the Blues move fourth with 12 points in 7 outings.
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