Jose Mourinho has praised Romelu Lukaku for the impact he has made at Manchester United and says the Belgian striker won't be rested.
The 24-year-old has scored 10 goals in nine appearances for the Premier League title-challengers.
He has missed just one game this season, when he sat out the 4-1 Carabao Cup victory over Burton Albion.
With the Red Devils short of attacking options, until Zlatan Ibrahimovic returns to fitness, Mourinho says he will continue to reply on Lukaku to be their primary goalgetter, although the likes of Marcus Rashford, Anthony Martial and Henrikh Mkhitaryan have all been weighing in with goals of their own recently.
Ahead of facing Crystal Palace on Saturday, Mourinho said: "Without Zlatan, we cannot rotate the striker, especially because Marcus Rashford is playing also in other positions.
"So until the moment we have Zlatan, we cannot think about giving rest to our number nine the same way we give in other positions."
On the rise and rise of Lukaku, who Mourinho feels has improved steadily over the years, he added: "Every step in his career, he grabbed it with both hands, since his first loan to West Bromwich Albion.
"He grabbed that opportunity with both hands, fighting for his evolution.
"He was very strong in his desire to be playing in a team with other objectives now and with Champions League football. It was always his dream to come to this level.
"Of course now, Manchester United is a different level of expectation and he is coping well."