Odemwingie is struggling with a knee injury while Thomas suffered a calf injury against Arsenal.
West Brom boss Roberto Di Matteo told the Birmingham Mail: “Peter and Jerome are both struggling for us – they’re not training at the moment.
“Peter has a problem with his knee. He over-extended it towards the end of our last game against Bolton so it’s good we had an international week but he’s still not okay.
“It was swollen after the game and we’d hoped he’d recover more quickly but the damage was worse than we thought.
“He had a scan and it’s nothing serious but he needs more time.
“At the end of play Tuesday it was still too early to say if they will be okay for the weekend.
“If they join us before Thursday then they have a chance.
“If they miss the game then we will have to slightly change our game plan on Saturday.
“We will see what options are available.
“We have 10 players away on international duty so we hope they come back okay.
“Graham Dorrans had a problem with his hamstring last week but he should be okay.
“The rest are fine, touch wood. I watched the games with my fingers crossed.”
