The New Zealand international missed Sunday's loss to the Melbourne Victory because of a virus but will be back to take on the Reds in what is shaping up to be a very important clash as Gold Coast strive for a top-four finish.
But as Smeltz returns, United coach Miron Bleiberg is sweating on the fitness of key midfielder Bas van den Brink and left-back Adama Traore who are both under injury clouds.
Dutchman van den Brink twisted his knee in a challenge with Victory midfielder Grant Brebner on the weekend and is in major doubt for Skilled Park fixture.
"Bas will have an MRI later today and hopefully we will get a nice surprise and he will be okay, but it's no better than a 50/50 chance at this stage," said Bleiberg.
"Given the short turnaround between matches it's fair to say that there are big question marks about both of them, but we will be positive until we hear otherwise."
Fourth-placed United meet third-placed Adelaide in the Week 25 midweek clash in Robina - kick-off is at 8:00pm local (9:00 AEDT).