West Ham boss David Moyes is set to make a late call over whether Ben Johnson will be fit to feature against Lyon on Thursday.
The right-back returned from international duty with some discomfort in his hamstring suffered while making his England Under-21s debut away in Albania last week.
Moyes decided not to risk Johnson in Sunday's 2-1 win over Everton, leaving the 22-year-old out of the matchday squad altogether.
It is not thought to be too serious an injury, but while Moyes is hopeful that the full-back will be able to feature in the first leg of West Ham's historic Europa League quarter-final against Lyon, his exact status remains uncertain.
Ryan Fredericks started in place of Johnson against Everton and, despite doing well at times, he can be a liability at the back. West Ham have at least been boosted by Vladimir Coufal's return after a hernia operation.
The Czech international was named on the bench on Sunday but did not get a chance to feature ahead of Lyon, which may be a concern if Johnson is not fit to return.
The same cannot be said for Jarrod Bowen, who played 70 minutes on his return from an ankle injury and grabbed the winner against Frank Lampard's ailing Everton.
"That's what you want when you've been out," said Bowen. "It's been annoying with the timing but injuries happen on your journey and to come back into the starting XI and get the goal and three points, you can't ask for much more.
"Obviously I'm not going to be where I was before I got injured, but it's about building that up game by game and just getting confident in it. I'm happy to score and get the win."
