In other notable selection news, Port Adelaide and Essendon made five changes each, Clayton Oliver is back for Melbourne, while Carlton dropped Sam Docherty but named star forward Charlie Curnow.
Barrass has played all eight games for the Hawks (6-2) since his high-profile move from West Coast at the end of last season.
But the 29-year-old will sit out the encounter with the Demons at the MCG on Saturday as Mitchell and his coaching staff take a long-term view on player management.
"When we recruited him, we didn't think he'd play every game for the season," Mitchell said.
"We thought the chance of him playing every minute of every game consistently was going to be difficult.
"He could play (this week), but we're going to manage his training loads to make sure we get the best out of him for the whole season.
"It wouldn't surprise me if we do that, from this point on, a couple of other times through the year."
Fellow senior players like in-form veteran Jack Gunston could also be rested in the coming weeks.
Karl Amon has been named to replace Barrass.
Oliver is back for Melbourne after missing last week's win over West Coast due to personal reasons.
But Viney has been ruled out due to delayed concussion after copping a whack to the face from young Eagle Bo Allan.
Forward Jacob van Rooyen has earned a recall to bolster Melbourne's forward line, with Jake Melksham (managed) and Harrison Petty (concussion) going out of the side.
Treloar made his return from a calf injury in last week's win over Port, but he has been ruled out of Saturday night's meeting with Gold Coast due to calf tightness.
The Suns have named Malcolm Rosas Jnr for his first game of 2025 and Ben Long also returns among four changes.
Lachie Weller (hamstring) and Connor Budarick (omitted) are among the outs.
Port forward Willie Rioli will miss Saturday night's showdown with Adelaide after copping a one-match ban from the AFL for sending a threatening message to an opponent.
Will Lorenz, Jordon Sweet, Logan Evans and Joe Berry were all axed in the wake of last week's 90-point loss to the Bulldogs.
The Crows welcome back Mitch Hinge from suspension at the expense of Brodie Smith.
Essendon named debutants Lewis Hayes and Archer Day-Wicks amidst their five changes for Saturday's match against Sydney, with Dylan Shiel and Jye Caldwell also amongst the ins.
Jordan Ridley, Jade Gresham and Harrison Jones go out through injury, while Jye Menzie and Elijah Tsatas were dropped.
Sydney replaced the suspended Lewis Melican with Ben Paton.
A training-session collision hasn't been enough to rule out Curnow for Friday night's crunch clash with St Kilda, while Jack Silvagni returns from a hand injury.
St Kilda welcome back Mattaes Phillipou for his first AFL match of the season.
