Christian Pulisic could miss the start of next season with a hamstring problem.
The American suffered the injury during Chelsea’s FA Cup final defeat against Manchester United.
And Blues boss Frank Lampard has admitted that Pulisic is “touch and go” for the start of next term. The season is due to get under way on 12 September.
Pulisic has produced some outstanding performances in his first year at Chelsea but has been hampered by injuries.
He struggled with a groin problem before battling his way back to fitness and was in superb form before his latest setback.
“With Christian Pulisic I think it’s going to be touch and go for the start of the season,” Lampard said.
“We´re probably looking around a six-week injury. So with six weeks, doing the maths, it gets very close to, and is probably into, the start of the new season.”
Cesar Azpilicueta also suffered a hamstring injury during the cup final and is unavailable for Saturday’s Champions League game against Bayern Munich.
But N’Golo Kante and Ruben Loftus-Cheek are in the squad for the game.