PROMISING Adelaide midfielder Rory Atkins will spend up to three months on the sidelines after injuring his knee at training.

Atkins, drafted by the Crows with pick No. 81 at the 2012 NAB AFL Draft, had been one of the more impressive young players this pre-season after almost breaking through for his senior debut last year.

The left-footer was selected as senior emergency twice and averaged 19 possessions a game at 80 per cent efficiency in the SANFL, finishing sixth in the club's SANFL best and fairest.

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Atkins damaged the posterior cruciate ligament in his right knee and, while he'll avoid surgery, the 20-year-old will wear a brace for several weeks.

Crows' head of football David Noble said he believed Atkins would apply the same attitude to his rehabilitation that he had to his pre-season.

Rory Atkins is a $120,000 midfielder in NAB AFL Fantasy this year. Create and fill your AFL Fantasy Classic league by March 2 to win a free AFL Live pass.