Marshall has been struggling with injury throughout training camp having undergone hip surgery during the off-season, and the 29-year-old aired his frustrations publicly last week.
However, despite Marshall being unhappy with his personal performance in pre-season, Emery believes that he is, in fact, better than he has ever been.
"He's going to get mad at me for saying this because I've been telling him all summer. I see a guy that's better than he was last year. I see a guy that's more dynamic. I see a guy better in and out of his breaks. I see a stronger player," Emery told ESPN.
"He's at an elite level for his position in terms of size, dynamic ability, production. I don't see any back-off. Actually, I see a better player. Obviously, he was a little frustrated about where he's at, and he's definitely shared that with [me]. Those are conversations that we've had.
"That's just an athlete wanting to be elite, wanting to be the best at his game. His goal is to be the best wide receiver in the NFL on the best team. I've got no problems with those goals."
Marshall is expected to be fit enough to start his side's opening match of the season against the Cincinnati Bengals on Sunday.