Midfielder Fleck has missed the Blades' last three games with a groin problem while forward McGoldrick sat out the midweek win over Wolves due to an ankle problem.
Chelsea midfielder Billy Gilmour will miss the remainder of the season after knee surgery.
N'Golo Kante remains out of action with a hamstring issue, but fellow midfielder Mateo Kovacic is fit again after a knock.
Fikayo Tomori is closing in on a return, but boss Frank Lampard has said the centre-back will not be ready in time for the Bramall Lane trip.
Sheffield United provisional squad: Henderson, Moore, Verrips, O'Connell, Robinson, Basham, Egan, Baldock, Stevens, Berge, Norwood, McBurnie, Sharp, Mousset, Zivkovic, McGoldrick, Jagielka, Rodwell, Osborn, Lundstram, K Freeman, Fleck.
Chelsea provisional squad: Arrizabalaga, James, Zouma, Christensen, Azpilicueta, Jorginho, Barkley, Mount, Willian, Giroud, Pulisic, Caballero, Rudiger, Alonso, Loftus-Cheek, Kovacic, Pedro, Hudson-Odoi, Abraham, Batshuayi.