Christian Pulisic and Andreas Christensen are both doubts for Chelsea’s London derby against West Ham on Wednesday.
Winger Pulisic, who has scored two goals in three appearances since football returned following the coronavirus outbreak, came off as precaution in the 1-0 FA Cup win over Leicester on Sunday.
And centre-back Christenesen missed the quarter-final victory at the King Power Stadium with a hip problem.
“Christian felt a bit of tightness in his calf in the game against Leicester,” Lampard said. “We are managing him and we haven’t got an answer yet.
“Andreas is in the squad but will have to see with another 24 hours.”
Meanwhile, Lampard has insisted there is no prospect of Chelsea signing Angel Gomes despite reports the youngster could move to Stamford Bridge after rejecting a contract offer at Manchester United.