The 2018 Brownlow medallist went under the knife this week and will be out of action for up to four months.

Mitchell missed the entire 2019 season due to a broken leg but was able to feature in all 17 games for the Hawks this year.

The 27-year-old finished runner-up in Hawthorn's best-and-fairest, only beaten to the Peter Crimmins Medal by forward Jack Gunston.

Mitchell's Hawks teammate Conor Nash also required shoulder surgery, with the Irishman to miss about the same length of time.

Mitchell posted a photo of the pair together with their arms in a sling on social media: "2020 in a nutshell".

Hawthorn physical performance manager Luke Boyd said both players won't rejoin training until the early part of next year.

"Like with a lot of footballers, Tom has had a grumbly shoulder joint for a number of years and it's something he has managed well over his career," Boyd said.

"Both these surgeries were the type that could wait until the end of the season, which now gives the pair a good chunk of time to focus on their rehab."

Despite upsetting premiership fancies the Brisbane Lions and Richmond early in the season, Hawthorn slumped to finish 15th on the ladder and record only five wins.

Australian Associated Press