With the new year upon us and all 18 clubs getting stuck into the thick of pre-season, it's time to remind ourselves who are the front-runners in each position across the league.

Here is our list of the top 10 defenders in the league heading the 2021 season.

See also:

The TEN best midfielders heading into 2021

The TEN best ruckmen heading into 2021

The TEN best forwards heading into 2021

9. Tom Jonas

Port Adelaide skipper Tom Jonas has been consistent for the past couple of years after picking up leadership duties from Travis Boak in 2019. The veteran earned an All-Australian nomination last season, as well as finishing third in the club's B&F. Jonas averaged 6.1 spoils per match, and was instrumental in Port's spirited run to the preliminary final.

ADELAIDE, AUSTRALIA - AUGUST 04: Tom Jonas of Port Adelaide during the round 20 AFL match between the Adelaide Crows and the Port Adelaide Power at Adelaide Oval on August 4, 2018 in Adelaide, Australia. (Photo by Mark Brake/Getty Images)