He is expected to go straight back into the starting line-up after withdrawing from Scotland the B international against Northern Ireland in midweek in order to prepare for the Blades showdown.
On-loan Watford midfielder Lee Williamson remains absent and will miss both legs of the semi-final due as he serves a three-match ban.
The 25-year-old endured play-off final heartache with Leeds at the Millennium Stadium against Watford in 2006, while Blades team-mates Leigh Bromby, Chris Morgan and Darius Henderson have been involved in previous play-off campaigns.
Kilgallon told the Star: "Everyone knows what's at stake. They are massive occasions.
"I've been there before and they are very tense because nobody wants to make a mistake. Everyone, every single player out there is like that.