Winger Dallas has missed United’s last three games with a calf injury that the Northern Ireland international picked up during the recent international break.
Whites head coach Garry Monk had initially hoped that the 25-year-old would return for Saturday’s clash at Wolves but next weekend’s Championship hosting of Burton Albion will now be the winger’s earliest possible return.
But United’s no 10 Hernandez has a definite chance of featuring on Tuesday evening after failing to make the match day squad at Wolves due to a dead leg that the Spaniard picked up during the 1-1 draw at home to Wigan Athletic last mid-week.
Asked if there was any chance of Dallas featuring against Norwich, Monk said: “Not for Tuesday.
“Pablo has a good chance - he’ll be out there training tonight but with Stuey we are hoping for the weekend.
“Of course I think both teams will make changes.
“We will have a good training session tonight, I will have a look at them and make a decision on the team.
“Whatever team is picked will go out there fully understanding what is expected of them.”