The 27-year-old, who was left out of last weekend's derby against Manchester City, came through United's youth ranks and has chalked up 138 goals in 426 appearances for the club since making his debut in 2016.
However, he has struggled for form over the last 18 months, losing his place in England's squad for the Euros in the summer.
Amorim's bold decision to leave out the forward against City was followed by Rashford's interview with British journalist Henry Winter on social media on Tuesday in which the forward revealed he was ready to end his 20-year association with United.
Rashford's comments were put to Amorim at a Wednesday press conference scheduled to preview nominally the club's League Cup quarter-final at Tottenham.
"No (I've not spoken to him)," Amorim said. "Not yet. It was yesterday (when) I gave the day off to the lads, so he's our player and he's ready for the next game."
Asked if he would be happy to retain Rashford in his squad, the recently-arrived Amorim replied: "Of course, because this kind of club needs big talents and he's a big talent.
"So, he just needs to perform at the highest level and that is my focus. I just want to help Marcus."
Amorim added the "new challenge" Rashford spoke of could be found at Old Trafford in trying to revive the fortunes of United, once the dominant force in English football, but now a lowly 13th in the Premier League.
"We have here a new challenge, it's a tough one," he said.
"For me, it's the biggest challenge in football because we are in a difficult situation and I already said that this is one of the biggest clubs in the world.
"So, this is a really new challenge and the biggest one. I hope all my players are ready for this new challenge."
© 2024 AFP