At 9-1 this season and a career 12-1 for the Calgary Stampeders, Mitchell has navigated his learning curve with a little help from Calgary's receivers, running backs and defence.
Among starting quarterbacks in the CFL, Mitchell has the highest quarterback efficiency rating at 100.5 per cent. That's a number based on completion percentage and yards, touchdowns and interceptions per attempt.
No quarterback in CFL history has won 12 of his first 13 starts. With 15 touchdown passes, Mitchell is second only to veteran Toronto Argonauts quarterback Ricky Ray with 16.
There was suspense when training camp opened whether it would be the inexperienced Mitchell taking over for the departed Kevin Glenn or would it be Drew Tate, the once-heir apparent.
In Calgary's first three wins, Mitchell had big assists from a defence that held the opposition to seven, 15 and eight points respectively.
But the 24-year-old from Katy, Texas, didn't force a quarterback change with a run of major mistakes those first few games. Each performance gave him the ball for the next game and Mitchell has taken ownership of the role.
The quarterback made his biggest impact yet in a game in Saturday 41-34 win over the Eskimos in Edmonton. Mitchell threw for a pair of touchdowns and ran for two more.
"He's always had great talent and makes some great throws, but I think he's been more consistent and he's been very patient lately," Stampeder offensive co-ordinator Dave Dickenson said Tuesday.
"He lets teams decide where the ball should go instead of forcing it in there. His leadership has taken a stride forward as well. You don't even know if you're going to be the starter during camp. It's hard to just jump in there and decide to take over. He's done a good job and has the 10 games in now."
Mitchell says it's not so much that the CFL game slows down as he gets games under his belt, but his on-field vision expands.
"The slowdown process probably happens a little earlier in your career as far as learning the speed of professional players," Mitchell explained.
"As you grow older and you play more, your field of vision becomes wider, if that makes sense. You're not so much locked into one thing and that's what you see. The peripherals really start to open up and you're actually able to see a lot more of the field and see the guys.
"It's working good, but as an offence, me and the receivers are all getting used to each other and we're coming into our own right now and things are starting to go well."
Calgary is coming off important back-to-back wins over Edmonton (7-3) which separated the Alberta rivals in the West Division. The Stampeders are at home to the Toronto Argonauts (3-7) on Saturday.
Mitchell scored a combined five touchdowns with his arm and legs and threw for almost 500 yards over the two-game series versus Edmonton. He wasn't intercepted in either game.
Star running back Jon Cornish's performance since his return from injury has also boosted Calgary's offence. Cornish, who sat out six games in July and August with concussion symptoms, posted his second straight game of over 100 yards rushing Saturday.
The CFL's most outstanding player last season was named the outstanding Canadian player a second straight week.
Mitchell demonstrated his own running ability in the third quarter Saturday. He dodged three Eskimos on a 20-yard scoring run to extend Calgary's lead to 31-10.
"People aren't expecting me to run. I'm not a design run-play runner," Mitchell said. "I'm going to take off when the chance and opportunity are there."
It was reportedly on that rushing touchdown that Eskimos cornerback Pat Watkins yelled a homophobic slur at Mitchell loud enough for television microphones to pick up.
Watkins and the Eskimos apologized in Edmonton on Monday when the Stampeders had the day off. Mitchell gave a statement Tuesday, but would not take questions from reporters.
"I appreciate Pat Watkins apologizing," the Calgary quarterback said.
"I know the comment was directed towards me and not towards the people he does offend. With all the microphones there are today, I don't think there's any place for the comments whether it's homosexual, anti-Semitic or racist in the game, out of the game, society, period."
Mitchell has managed to stay healthy and in each game, in contrast to several CFL teams who have played their backups for long stretches. Saskatchewan's Darian Durant and B.C.'s Travis Lulay were the latest to go down this past weekend.
Durant is likely out for the remainder of the regular season after suffering a torn tendon in his elbow Sunday. Lulay sustained his third shoulder injury in as many years Saturday in Ottawa and is on the six-game injured list.
"My heart goes out to those guys, especially those two doing what they've done," Mitchell said. "They've both won a Grey Cup and been in the league and have been playing very well for along time.
"To see someone work so hard at their craft and have it taken away from then, not because of performance or anything like that, but just because of bad luck, it's hard to see."