The 27-year-old left Man United for Aston Villa in January, impressing since making the move and earning a re-call to the England set-up.
Rashford has scored three goals and providing four assists in his 13 games across all compeitions for Unai Emery’s side.
Despite that, Foster doesn’t believe Rashford is entirely suited to Villa’s style of play and doubts whether the club would be willing to pay the reported £40 million asking price.
Foster told the Fozcast, via the Mirror: "I don't know if Rashford is going to be the answer. When he came on in the Forest game the other day, they were 2-0 up at the time and I was thinking, 'What would Rashford's objectives be here?'
"I think when Emery brought him on, he would've said, 'right Marcus, we're 2-0 up and Forest had some good chances in that first half. I'm going to need you to get hold of the ball for me. I'm going to need you to try and get it down and get us up the pitch'.
"There were a couple of times where they went long to him, and he was not willing to stick his head up there. He's not willing to get hurt physically and the ball just came back."