Carlton's Patrick Cripps has suffered a stress reaction in his lower back that will sideline the young midfielder for up to 12 weeks.

The 21-year-old experienced discomfort during Wednesday's training session and scans today revealed the injury.

“Unfortunately this pre-season setback means Patrick will be out of action for up to 12 weeks,” Carlton’s Head of Football Andrew McKay said.

“While the news is disappointing, the positive is we have diagnosed the condition early, minimising his time on the sidelines.

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