STEFAN Martin already loomed as a major stumbling block for North Melbourne this week, but the challenge might be tougher than first thought.

The Kangaroos are facing a ruck shortage entering the round 23 clash with the Brisbane Lions at the Gabba, with Todd Goldstein and Braydon Preuss in a race against time to be fit.

The teams are locked on five wins, so the loser will claim the wooden spoon and gain access to the No.1 draft pick – likely to be Western Jets midfielder Cam Rayner. North last finished on the bottom in 1972, so it would be a significant event.

No.1 big man Goldstein sustained a scratched eye and a left knee injury in Sunday night's 49-point defeat to finals contender St Kilda. Exacerbating the problem was the fact Preuss hurt his right shoulder in the second quarter.

Both Goldstein, 29, and Preuss, 22, face fitness tests this week, with the 2015 All Australian most in doubt after ending the Saints match on the bench with ice on his knee.

The Roos already ruled out Majak Daw (foot), while two-gamer and back-up ruck-forward Nick Larkey has missed the past fortnight and is still in doubt with ongoing knee issues.

Ben Brown, who is fourth in the Coleman Medal race with 56 goals, served as a relief ruckman throughout the season, but may be forced into a bigger role in the worst-case scenario.

Martin is one of the competition's most formidable ruckmen, averaging the third-most hit-outs (35) to go with 17.5 disposals, four marks and 5.3 clearances.

The Roos have one of the lengthiest injury lists in the League. Dan Nielson (concussion), Jack Ziebell (foot), Cameron Zurhaar (back) and potential inclusions Jarrad Waite (calf), Mason Wood (calf) and Corey Wagner (ankle) will all undertake fitness tests.

But there could be some relief, with rebounding defender Aaron Mullett (calf), who missed last week's contest, not on the injury list and set to return.