BRISBANE defender Marcus Adams has succumbed to another foot injury that will delay his return to football in 2020.

The 26-year-old is set to undergo surgery in coming days to repair a foot/heel issue that flared while training in isolation.

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While the Lions attempted to let the injury recover through rest, the West Australian met with his surgeon on Monday where a decision was made to operate.

The latest setback, which comes after a history of foot problems, is set to sideline Adams for a minimum of 4-6 weeks.

Adams played the final 10 games for the Lions last year – including two finals – and became a first-choice key backman after sitting out the first 15 weeks due to a knee injury that required surgery. 

Then, after foot problems dating back to his time at the Western Bulldogs from 2016-2018, he battled another setback this pre-season before he was cleared to play in round one.

After delisting Josh Walker at season's end, the Lions' key defensive depth falls to Matt Eagles and Jack Payne behind Harris Andrews and Darcy Gardiner.

Meanwhile, ruckman Stefan Martin is out of his knee brace after suffering PCL damage in the Lions' round one loss to Hawthorn.

He will be assessed by Lions' medical staff when players are allowed to return to training – potentially at early as May 18 – with a view to ramping up his change of direction running.