Dimitar Berbatov's groin injury is not serious but he will miss the club's next Premier League game at the weekend, according to the player's agent.
"I can't say when exactly he will be ready to play," Danchev told Bulgarian Darik radio.
"He'll definitely miss the Derby County match but I hope he'll recover in time to play for the national team.
"He felt some pain in his adductor muscle in the last minute of the Everton match on Tuesday.
"The scan revealed that he sustained a niggling strain and he flew to Munich for consultations."