The defender was forced off with an ankle injury early in the second half of the home league defeat to Aldershot in midweek.
He will continue to be assessed but Andy Corbett, Austin`s replacement on Tuesday night, and Tony James are on standby. Midfielder Russell Penn is nursing a thigh strain and he will also face a late check.
Burton became the first side to inflict a home league defeat on Chesterfield just two weeks ago but the Brewers have lost back-to-back home game since.
Aaron Webster`s 85th-minute effort earned Burton a 1-0 win over Oxford in the previous round.
Source: PA
Source: PA