Manchester United will face Chelsea at Stamford Bridge without a recognised forward on Monday after Wayne Rooney, Marcus Rashford and Anthony Martial were all ruled out by manager Jose Mourinho.
FA Cup holders United were already without the suspended Zlatan Ibrahimovic for the quarterfinal tie against the Premier League leaders.
But United sources have confirmed to ESPN FC that Rooney and Martial will miss out due to injury, with England youngster Rashford left behind because of an illness.
All three players failed to join the rest of the United squad as they boarded a train to London from Stockport on Sunday afternoon, with sources subsequently confirming the reason for their absence.
Rooney, who missed the Europa League round-of-16 trip to Russia for last Thursday's 1-1 draw against FC Rostov, was injured in training on Sunday following a collision with teammate Phil Jones.
Without a senior forward to turn to, Mourinho is now expected to play Marouane Fellaini at centre-forward with Juan Mata or Henrikh Mkhitaryan in the nearest supporting role.
On Thursday, United host Rostov at Old Trafford. Ibrahimovic, who starts a three-game domestic suspension against Chelsea, will be available for that match.