Simpson turned down the Eagles' offer of a farewell game this week, officially ending an 11-year tenure that included the 2018 flag.
Mitchell played under the 48-year-old at both West Coast and Hawthorn, where Simpson was an assistant to Clarkson before landing the senior role at the Eagles.
"Simmo's got a great footy mind and there's not many premiership coaches out there, so he's done a great job," Mitchell said.
"Right now everyone's thinking about this little period, but he'll be remembered as a premiership player and premiership coach.
"He's got one of the great resumes, and you don't want to lose the best people around.
"Hopefully he'll come back to footy when the time's right for him."
Clarkson was also confident Simpson would return to the coaching scene when ready.
"Like all of us, when you first remove yourself from it or get removed from it, the best thing is just let the dust settle for a while," he said.
"You're just in so much overdrive, especially in season.
"So he and (his wife) Nicky and the kids will just have a spell for a little while and then I think he's on record as saying Nicky wanted to kick him out of the house after a day, so I'm not sure how long he's gonna last.
"But he'll get back involved in footy I'm sure at some point in time. It'll be a real asset for the game if he does continue to be involved."
Simpson was informed on Monday night West Coast wanted to have a fresh start with a new coach after a rough three years, which included a bottom-two finish in 2022 and wooden spoon last year.
The Eagles won just 10 of Simpson's last 70 matches in charge during that period.
Mitchell was "disappointed" in some of the media coverage around the latter stages of Simpson's reign.
"We've been close for a long time so I feel for him, but he's a great person and none of those things change," Mitchell said.
"I'm not concerned for his future.
"He's got a great family, great person ... he's going to come through this without too many scratches, I'd imagine."
Mitchell echoed Port Adelaide coach Ken Hinkley's recent observation that intense pressure and scrutiny were part of an AFL coach's job.
"It's always someone's turn in this game," Mitchell said.
"There's other coaches that have been under the gun and under enormous amounts of pressure this year even when their side are going reasonably well.
"That's the nature of the media circle at the moment ... it's the nature of the job and it's what we get paid to do.
"You're the face of the club, and when the club's not going well you bear a lot of it."
