ADELAIDE defender Luke Brown will be sidelined for two months as he undergoes surgery to his left ankle.

Crows high performance general manager Matt Hass said Brown would have plantaris surgery this week.

"Luke’s plantaris tendon is limiting his ability to complete the pre-season loads required to prepare for AFL football," Hass said.

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"He had progressed well with conservative management of an ankle impingement issue through the pre-season, but with a return to full training the plantaris tendon is now causing symptoms that limit him.

"He will undergo surgery to the tendon and ankle this week."

The 25-year-old had been on modified training for the past few weeks after aggravating an ankle and Achilles injury he sustained last season against Fremantle.

Brown, regarded as one of the elite small defenders in the competition, has played 135 games for the Crows.