Gracia will return to the Vicarage Road dugout for the first time since August 2019 for the visit of the Baggies after losing his opening match 1-0 at Bramall Lane .
Caleb Wiley has been "feeling some pain" this week and may miss out, while Giorgi Chakvetadze remains sidelined and Othmane Maamma has not yet returned after Morocco's triumphant Under-20 World Cup campaign.
The Spaniard should have a fully-fit squad available to him otherwise, though.
He said: "We have had one chance to show what we are and I think we didn't play at our best level, we didn't show our best face.
"We have many things to improve but on the other hand I'm sure we have the qualities and skills to do it.
"We have to work harder and insist on the important things to be a solid team, to compete better, and to do it from our next game tomorrow.
"Being fair, with the chances we had we could have got a better result. But I'm not only thinking about the final result - I'm thinking about the way we competed.
"We have to analyse and be demanding with ourselves and then I'm sure day-by-day, game-by-game, we will improve."
On the grind ⚙️ pic.twitter.com/gOpGwfxigV
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Gracia left James Abankwah, James Morris, Jeremy Petris, Pierre Dwomoh and Vivaldo Semedo out of the matchday squad completely in South Yorkshire.
A few players will always be absent while injuries are not stacking up - particularly at centre-back, where there are five options for two spots in a back four.
He said: "It's tough for me, it's the worst thing I have to do.
"To take these decisions was never easy for me, but now when I have a big squad I put four or five fit players out of the list. It's difficult.
"Centre-back is not the only position where we have more than two players. At left-back we have three players. We have three number nines with similar qualities, all tall and all left-footed.
"It is hard to manage but it depends on them as well. If in every training session they show me they deserve to be in the team, in the squad, then I do it.
"I don't have any preference in this moment. I only want to find the best players for each game."