Mitchell, who joined the Eagles after 307 games at the Hawks, has already made a huge impression during pre-season training.
Simpson said that the 34-year-old, who will become an assistant coach at the club following his playing days, is like an on-field coach.
“Already he’s having an impact around the club, so he’s exactly what I thought he’d be,” Simpson said.
“He has empathy for the player and he can educate, which, when you have a player like that who can extend your coaching ranks on-field, I think he complements our leaders really well.
“All of our leaders have that ability as well, so he just adds to the numbers – along with Drew (Petrie).
“(Mitchell) won’t be captain, but there’s a strong chance that he gets voted in by the players to be one of our leaders.
“He’s fitted in really well. We know his history and his credentials as a Hawthorn player, but he’s settled into the club and the state really well.”
Veteran Shannon Hurn is expected to retain the captaincy when the playing group vote in on the leadership group the coming weeks.