Sheffield United injury problems added to by international break
All three went away with their countries but Greek international Baldock and Danish under-21 Osula did not play.
"George picked up an injury, Will picked up an injury, Eags picked up an injury, so everyone who went away has come back injured apart from Davo (Adam Davies)," said Heckingbottom, who has no fresh injuries from those who stayed behind to train.
Anel Ahmedhodzic is back in training after the thigh injury which saw him miss international duty with a thigh problem, to the anger of Bosnia and Herzegovina.
"It was a mountain made out of a molehill," said Heckingbottom. "We were worried about his thigh and he had some hamstring injuries.
"He did speak to three people at the Bosnian FA who all knew about it and from his past experience when he'd been away and came back injured and he wasn't looked after as well as we'd possibly want. He knew he wasn't fit to play and he wanted the best possible treatment to get fit and to get training as quickly as possible.
"We've got him back on the grass and available now.
"He knows I'd never stop anyone playing for their country but I think he has been really sensible and he's got himself fit in these days."
Egan was substituted against Everton with knee and ankle injuries but played in the Republic of Ireland's Euro 2024 qualifiers against France and the Netherlands.
Meanwhile it has emerged that a little-known Premier League rule prevents clubs from omitting players over the age of 21 from their squads to make space for signings unless they have more than the permitted 25. It had been expected that the Blades might leave an injured player to allow them to sign an out-of-contract player.
The Blades named 25 senior players on Wednesday.