Heckingbottom, who has been out all season, played the full 90 minutes in the reserve team's 3-2 win against cross-city rivals United yesterday and claims he is ready to come back into Paul Sturrock's reckoning.
Current left-back John Hills has missed training this week with an illness and The Owls boss could be forced to bring former Norwich star Heckingbottom back for the Derby game on Saturday.
Diallo meanwhile played in the first half against The Blades and capped off a decent performance with a goal - but he will take a bit more time to be ready for a starting place.
With Graham Coughlan out until Christmas, Richard Wood has regained his place alongside Graeme Lee in defence although with Lee Bullen and now Diallo eager to get back into the team, both will have to be on their toes.