A Magpie has reportedly suffered his second concussion in three months, joining a concussed Blue on the sidelines as the AFL ponders limiting clubs' contact training sessions to reduce the risk of head injuries.

Midfielder-forward Josh Carmichael is said to have sustained a head knock at a Magpies pre-season training session, culminating in a second such incident this week across the league.

The 24-year-old South Australian, who managed just one senior game for Collingwood in 2023, suffered the concussion during Monday's session, per Herald Sun journalist Jay Clark.

It is understood Carmichael will be sidelined for the remainder of the Pies' pre-Christmas sessions and is expected to rejoin the fray early next year.

MELBOURNE, AUSTRALIA - JULY 30: Josh Carmichael of the Magpies runs with the ball during the round 20 AFL match between the Collingwood Magpies and the Port Adelaide Power at Melbourne Cricket Ground on July 30, 2022 in Melbourne, Australia. (Photo by Daniel Pockett/Getty Images)

Monday's incident represents the second concussion in a matter of months for the West Adelaide product, who suffered a similar fate during Collingwood VFL's Wildcard Round outing in September; subsequently entering the league's concussion protocols.

Carmichael joins Carlton defender Mitch McGovern in falling victim to a concussion this week, as the defending Blue succumbed to the ailment during Monday's session and will miss the club's remaining 2023 training block.

MELBOURNE, AUSTRALIA - MAY 26: Mitch McGovern of the Blues looks on during the round 10 AFL match between the St Kilda Saints and the Carlton Blues at Marvel Stadium on May 26, 2019 in Melbourne, Australia. (Photo by Scott Barbour/Getty Images)

Taking into account State Coroner John Cain's findings following the death of concussion-laden Richmond footballer Shane Tuck, the AFL continues to weigh changes to league policy regarding the amount of contact training sessions each club can facilitate.

While changes are yet to be made, the current climate, coupled with last season's sling-tackle MRO crackdown, suggests the AFL is again likely to undertake a stringent approach to head-related ailments in 2024.