The duo limped off injured in last weekend’s win over Shrewsbury Town.
They both missed Tuesday night’s game with Bury, but boss Chris Wilder has revealed both are back on the training ground.
Wing-back Freeman and midfielder Duffy have helped the Blades go on a 14-match unbeaten run in League One, ahead of Saturday’s trip to Charlton Athletic.
“Freeman and Duffy are training today so hopefully they’ll come through and be available,” said Wilder. “We’ll see how they get on.
“Everybody came through the game the other day and so, pretty much, we’ve got a full compliment to pick from. That’s good because we’ve got a lot of games coming up.
“We’ll make decisions which are right for the football club. As we saw, when he lost Freeman and Duffy to injury, everybody has got to be ready to start at any given time. Because you just don’t know what’s going to happen.
“We won’t be scared to change a winning team. We look at the opposition, at our players and decide what gives us the best chance of winning the game.
“But I also understand that when players are in a winning team that they want to stay in.
“We’d have loved to have organised a few games in midweek but we’ve not been able to because we’ve been playing on Tuesdays quite regularly.”