The English midfielder was unable to last more than 20 minutes against Manchester City on Sunday.
Mount had started the game in an attacking midfield position, but had to be subbed off for Kobbie Mainoo due to injury.
Asked about Mount and Noussair Mazraoui’s fitness, Amorim stated: "It's more the problem with Mason and Nous. You think right away, you go in the tunnel and think right away because we have a lot of games, you know. We need to continue to win and it will change if we don't win the next game."
"Yeah, he really fits our style," he aded on Mount.
"He will continue to fit because he's a very good player. Also, outside of the pitch, he is the kind of character I want in this team and we want as a club in this team.
"He has a movement, it's not like something he made a sprint. He made a movement and stretched his leg and felt something.
"It's bad luck, nothing with the problem of the body of Mason Mount. It was a bad movement and he is going to recover because we need him."