Australia are sweating on the fitness of another key batsman, with Shaun Marsh the latest injury concern on the eve of the Ashes.

David Warner is confident of being fit for Thursday's opening Test in Brisbane, though selectors called in Glenn Maxwell as cover for the star opener, who is nursing a stiff neck.

Now Marsh, 34, is under an injury cloud due to a back problem as Australia start their bid to wrestle the urn back from holders England.

A surprise selection for the blockbuster series, Marsh – who has a history of back injuries – reportedly pulled up sore with a stiff back following training on Wednesday.

Marsh was recalled to the Test squad for the eighth time, selected to bat at number six, despite scoring just 236 runs at 39.33 so far in the Sheffield Shield this season.