Ben White was missing from England training on Monday because of illness, just one day ahead of the Three Lions' World Cup clash against Wales in Al Rayyan.
Gareth Southgate's side head into Tuesday's Group B match on four points but need a win to guarantee qualifying for the knockouts in top spot.
White enjoyed a fruitful campaign with Arsenal before heading on international duty, marshalling the Gunners to top spot in the Premier League with reliable defending at centre-half and right-back.
Although the England boss is unlikely to shuffle his tried and tested defensive partnership of John Stones and Harry Maguire against the Welsh, particularly after their important clean sheet during Friday's 0-0 stalemate against the USA, White's illness comes as a frustrating blow for the Three Lions.
Having created very little against the Americans, Southgate may be tempted to involve Leicester playmaker James Maddison, who trained on Monday in a huge boost for England.
The Three Lions had just one meaningful shot on target throughout the whole 90 minutes, while USA hit the crossbar and had plenty of chances to score.
Maddison has been nursing a knee injury sustained during the Foxes' final Premier League fixture before the World Cup break against West Ham but had trained with the rest of the group for the first time on Saturday.
Gareth Southgate revealed last week that the midfielder may return for the final Group B clash against Wales after he trained alone in a bid to speed up his recovery.
And, having come through that session and another one on Monday, it now looks like he should be good to play some part in Tuesday's game against Rob Page's side.
Harry Kane meanwhile trained with the squad as he continues to nurse a severely swollen ankle.
In the moments after the draw, in which Kane didn't look at full fitness, the England skipper went into the crowd to kiss his wife Katie Goodland and have a brief catch-up with his family.
However, in pictures, his right ankle, which was the same one that he had a scan on earlier last week after a challenge he received in the game with Iran, looked extremely swollen.
England fans will have to wait and see whether Southgate takes risks and rotates in his selection against Wales, but one man who will be keen for minutes is Phil Foden.
The Manchester City star was bizarrely left on the bench throughout the 90 minutes against Gregg Berhalter's side, but Southgate insisted Foden still has a major part to play for England in Qatar.
The attacking midfielder trained during Monday's session and was pictured on his knees during the session.
England are not expected to make major changes for their final clash, but it is understood Southgate is looking at alterations.
The Three Lions head into the fixture with Wales at the Ahmad bin Ali Stadium in Al Rayyan top of Group B knowing progress to the last-16 is assured as long as they avoid a 4-0 loss.