Smalling returned for United in the 3-2 FA Cup third round win over rivals Manchester City.
The 22-year-old has been out of action after suffering tonsilitis over the Christmas period.
Smalling told MUTV: “It was a frustrating Christmas and New Year for myself as I was pretty much laid up in bed for the whole time.
“But I’m fit and well now and I’m back in training so hopefully I’m over it and can play in the rest of the games.”
