Bell came off in injury-time at the end of Albion's 2-1 home win over Torquay last weekend after being on the receiving end of a heavy tackle.
Zola also failed to finish the game - but only after scoring Burton's opening goal in a victory that powered the Brewers back into the npower League Two play-off places.
The big striker suffered a recurrence of a groin strain that had prevented him from training since the FA Cup tie at Leicester on January 5.
Boss Gary Rowett has options should he need to replace either Bell or Zola, or opt to make changes to his starting line-up.
Defenders Aaron Webster and Marcus Holness, midfielders Jack Dyer, John McGrath and Jimmy Phillips and striker Matt Paterson are all vying for recalls.