Bristol City defender Damion Stewart will be assessed ahead of the trip to Millwall.
Stewart injured his ankle last week and missed the 4-2 defeat at Barnsley on Saturday.
"Damion looks better and perhaps the extra two days, having missed the Barnsley game, has done him good," boss Keith Millen told the club`s official website. "We will see how he is on Tuesday and make our selection appropriately.
"We managed to get the rest of our defence, including Louis Carey, through training unscathed, so that is good news."
Carey has been sidelined since suffering a fractured skull at the end of February.
Meanwhile, left-back Jamie McAllister, who was forced off against Barnsley with cramp, is expected to be fit.