ADELAIDE defender Brodie Smith will complete his recovery from a knee reconstruction with the security of a long-term contract after signing a three-year extension on Thursday. 

Smith, who was due to come out of contract at the end of this season, has committed through to the end of 2021.

The news comes after a challenging period for the skillful half-back, who ruptured his anterior cruciate ligament in last year's qualifying final win against Greater Western Sydney.       

"It’s been a difficult off-season for me with the knee reconstruction, but to be able to agree to a new deal is both comforting and exciting," Smith said.

"Adelaide is just a great club to be a part of and I’ve formed some really close relationships with players, coaches and staff who are all trying to get the best out of each other.

"I couldn’t imagine playing football anywhere else and I will be doing everything I can to get back out on the park with my teammates as quickly as I can."

Smith started running pre-Christmas and the Crows have been encouraged by his progress. The dashing defender is still expected to miss a significant period of the season, however, with the aim of making a late run for selection towards finals.

The Crows will miss the 2014 All Australian's run and drive off half-back and ability to push onto a wing, with Smith ranked No.1 at the club for metres gained in 2017, and No.2 for rebound 50s and effective kicks.

"Brodie is one of the most damaging running defenders in the competition who has a unique ability to break the lines," list manager Justin Reid said.

"Over the last few years, we’ve really seen him grow as both a player and a leader within the group.

"He’s approached his rehabilitation with a fantastic attitude and we look forward to him getting back to playing."

Smith, 26, was recruited with pick No.14 in the 2010 NAB AFL Draft and has played 143 games, including 21 or more in each of the past four seasons.