Western Bulldogs captain Marcus Bontempelli is said to be "in some doubt" for this weekend's clash against North Melbourne after leaving training early on Wednesday.

The star Bulldog was reportedly hampered by a back spasm at the club's main training session in the lead-up to Saturday's matchup with the Roos, according to 7 News reporter Mitch Cleary.

The ailment has cast doubt over Bontempelli's prospects for the Dogs' next game, with coach Luke Beveridge potentially losing arguably the best player in the competition against an in-form North Melbourne engine room ensemble.

Twice this year Bontempelli has shaken off illness to play, with performances those weeks being among the five-time best and fairest winner's best for 2024.

The Bulldogs are in line to make at least two changes to their squad to face the Kangaroos, with key forward pairing Aaron Naughton (knee) and Sam Darcy (suspension) likely to return.

Midfielder James Harmes is also a chance to face the Roos following a recent hamstring injury and could be a likely inclusion in the case of Bontempelli being absent this weekend.

The returns of both Naughton and Darcy could mean tall Rory Lobb, who has struck some of the best form during his time with the Bulldogs, makes way at selection.

Recruit Nick Coffield is also a test for this week following a shoulder injury sustained in March, with a return through the VFL likely.

The Bulldogs face North Melbourne at Marvel Stadium on Saturday at 1:45pm (AEST).