Rashford scored the first goal of the Amorim era on Sunday, finding the back of the net inside 90 seconds, but could not prevent United drawing 1-1 with Ipswich.
That goal was just his 13th in the Premier League since the start of last season, and his struggles have spread across the forward line with United scoring just 13 times across 12 league games this term.
"Of course there is a concern in that but I think we have to improve as a team," Amorim said. "Because we have quality players who can score so many goals. But you can feel it in the second half (at Ipswich).
Marcus Rashford in training on Wednesday
Action Images via Reuters
“We control possession of the ball but we were not dangerous. Maybe because we spend the week trying to work on build up and then the rest was not working.
"We will try to improve as a team and Rasmus (Hojlund), then Josh (Zirkzee) and Rash will score more goals, even Bruno (Fernandes) has to score more goals. Amad (Diallo) has to be better near the goal.
"All these guys need to improve, and we can score so many goals. You are trying to (ask) if I need a new striker to score goals. We need to improve as a team and these players can score more goals."
Homegrown forward Rashford is a case in point, having stumbled since scoring a career-best 30 goals in the 2022-23 campaign.
He has to be the first one to really, really want it
Ruben Amorim on Marcus Rashford
The 27-year-old has endured more downs than ups since then but has the trust of United's new manager, who had the England international leading the line at Portman Road.
"I will try to help him," Amorim said of Rashford, who has scored five goals in 19 appearances this term. "That position is not the best one for him, especially in a game like that. We have to keep with high pressure, we have to kick the ball so many times and it was like fighting with two giants.
"We'll try to find the right solution for him, as for the other players. But it has to be Marcus, first of all, to try to return to that moment.
"Then he will have the help of all the staff, the club and the fans because he's a Manchester United boy. But he has to be the first one to really, really want it."
_Additional reporting by Press Association._
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