Carlton co-captain Sam Docherty will head to Philadelphia over the coming weeks in a bid to continue to recover from back-to-back knee reconstructions.

According to AFL.com.au, the Carlton skipper will meet with conditioning expert Bull Knowles, who has also looked after Nic Naitanui, Jake Lever, Jon Patton etc. over the past few years.

Knowles has worked with American sporting teams and Olympic athletes over his career, helping them improve the strength and mobility in his knee.

Docherty hasn't played for Carlton since August 2017, after suffering back-to-back ACL injuries in pre-season.

The 25-year-old defender is currently contracted to the Blues until the end of the 2021 season, after signing a new one-year extension back in June.