Meanwhile, Cardiff have begun the campaign in strong fashion with two wins out of their three season openers.
But now the 28-year-old has built up his match fitness, he could find himself in the mix for a starting spot.
The Baggies will still be without striker Daryl Dike who could miss up to three months of action due to a thigh strain.
It is the American's second injury since joining the club in January, the first a hamstring strain picked up on his home debut for the club.
The injury will put his World Cup hopes in jeopardy with it likely to be a struggle to get him fit in time for the competition.
Albion loanee Cedric Kipre will miss out on Wednesday's clash as he is ineligible to face his parent club.
The Ivorian has put in some good performances since his arrival in Wales and will be a big miss for Steve Morison's side.
New signing Jack Simpson was thought to be able to replace him, however, the former Rangers man isn't ready for a full 90 minutes just yet.
The 30-year-old won promotion under Slaven Bilic in 2019/20 and made 64 appearances in his second spell at the club.
(4-2-3-1) Button, Townsend, O'Shea, Ajayi, Furlong, Yokuslu, Molumby, Diangana, Swift, Wallace, Grant
(4-2-3-1) Allsopp, Collins, Nelson, McGuiness, Romeo, Rinomhota, Wintle, Philogene-Bidace, Sawyers, O'Dowda, Etete
An impressive performance in the defeat against Blackburn Rovers means Diangana could be climbing back to his best after a difficult two seasons.
He failed to break into Sam Allardyce's Albion side in 2020/21 and struggled to fit into Valerien Ismael's physical and narrow forward line.
The winger is certain to be a key man if he can stay on form, and provide those vital contributions to keep the Baggies in a promotion hunt.
The forward has made a great start to life in Wales after signing from Bristol City earlier this summer.
Providing a goal and two assists since arriving, O'Dowda looks to be an astute acquisition for Morison's outfit as they look to build on last season's 18th-placed finish.
The Irishman will occupy the left hand channel and could provide a creative touch as the Bluebirds look to stifle Albion.
Where is the game being played?
What time is kick-off?
Kick-off is set for 20:00 pm (BST) on Wednesday, August 17.
Where can I watch?