Frank Lampard said Christian Pulisic came off in Chelsea’s FA Cup win against Leicester because of a slight calf problem.
Chelsea reached the semi-finals with a 1-0 victory at the King Power Stadium, where Ross Barkley scored the all-important goal.
Pulisic impressed again but appeared to be in some pain after coming off in the second half. The American will be assessed on Monday.
Lampard said: “He felt a tightness in his calf so I took him off straightaway. We’ll see in the next day or so.”
Blues boss Lampard also explained that Andreas Christensen was absent from the squad because of a minor hip problem.
Lampard’s changes pay off
Chelsea were poor in the first half and Lampard made three changes at the interval.
Youngsters Billy Gilmour, Reece James and Mason Mount were replaced by Barkley, Mateo Kovacic and Cesar Azpilicueta.
The impact was immediate, with Chelsea much improved in the second half and Barkley scoring with a neat finish from Willian’s cross.
Lampard admitted: “We haven’t played that badly since I have been here. We were fortunate to be 0-0 at half-time.
“I could have made seven, eight or nine changes. The subs changed it for the better
“The first rules of football are urgency and sprinting and not jogging. We were taking too many touches and we need to be brighter than that.
“If we turn up again like that in the future we have no chance. We were lucky to get through today. It was a lethargic performance.”
Tough day for Gilmour and co
It was a tough learning experience for midfielder Gilmour.
The Scot earned rave reviews for his previous first-team displays but this time was hooked after giving the ball away a number of times during the first period.
“It was one of those games where I had to do something,” Lampard said.
“They (the youngsters) will be top players for this club and have good careers but if I have to do something in games I will do.
“They will take it on the chin. We must learn from the mistakes.”