Carlton have suffered a major injury blow, with star midfielder Patrick Cripps set for an interrupted AFL pre-season after injuring his back.

Cripps will be sidelined for up to three months, with scans revealing he has suffered a stress reaction in his lower back after experiencing discomfort during training on Wednesday.

“While the news is disappointing, the positive is we have diagnosed the condition early, minimising his time on the sidelines,” Carlton football boss Andrew McKay said on Thursday.

“Given his professionalism and determination, we are confident Patrick will be ready for the 2017 pre-season competition.”

At just 21, Cripps is already widely considered Carlton’s most important player.

The powerful midfielder won the Blues’ best and fairest award in 2015 and was runner-up for the AFL Rising Star award.

He continued his strong form this year, placing third in the best and fairest count and averaging 27 disposals per game.

With players gradually returning to the track, Carlton’s list is otherwise relatively healthy.

Blues captain Marc Murphy has returned to full training after being sidelined for most of this season with an ankle injury.

New recruits Caleb Marchbank (shoulder) and Jarrod Pickett (foot) are on restricted programs, while Ciaran Byrne is continuing to recover after undergoing a knee reconstruction.