THERE is growing uncertainty surrounding Carlton's coaching panel, with senior assistant John Barker announcing his resignation.

Barker, who joined the Blues as an assistant coach in 2011 and has been working as stoppages coach under David Teague this season, will depart the club effective immediately during its bye week.

It's a move that has fuelled speculation that Carlton could be set to overhaul its coaching group at the end of another tumultuous season, where the Blues have started with a disappointing 4-8 record and look set to extend their finals drought to eight seasons.

Carlton launched an external review of its football department this week, with outgoing president Mark LoGiudice saying the club is "not satisfied with where we are at from a performance perspective" and promising to "leave no stone unturned" in its investigations.

He continued: "Rather than wait until the conclusion of the 2021 season to undertake this review, we feel the opportunity is available to formalise this now as we head to the halfway mark of the season."

Barker is the first departure following the announcement of the review, with club staff notified of his immediate exit on Monday evening. It's understood he had been seeking administrative positions within football last summer.

But more change has been tipped in the coming months, as the Blues seek to desperately improve on-field results following an active off-season where the club landed high-profile recruits Zac Williams and Adam Saad.

Barker, a highly respected figure at Ikon Park, had been into his 11th season at Carlton after joining the club following a 168-game playing career with Fitzroy, Brisbane and Hawthorn as well as assistant coaching roles with St Kilda and Hawthorn.

"I've absolutely loved my time in footy, and most of all I've loved the relationships I’ve built during my time in the game," Barker said.

"However, over the past 12 months I've been able to take the time to reflect on what's most important to me and given the nature of the role and all it commands, I've made the decision to explore other avenues outside of football, and most importantly with my family at the forefront of this decision."

He took the reins as caretaker coach of the Blues for much of the 2015 season following the departure of Mick Malthouse, guiding the club to a 3-11 record before just losing out in the race to win the role on a permanent basis to Brendon Bolton.