Graham Onions has a hamstring strain and was unable to take part in England practice this morning, on the eve of the first Investec Test against South Africa at The Oval.
Onions, included in England's 13-man squad as an extra pace bowling option, joined his team-mates for warm-ups but was not involved in this morning's net practice.
He has not yet been ruled out of contention to play tomorrow, but must be considered a significant doubt.
The Durham bowler was an outsider to be included as England's third seamer, in any case, with incumbent Tim Bresnan and also Steven Finn likelier choices in most minds.
There was other business to be settled for England this afternoon, with their 30-man preliminary ICC World Twenty20 squad set to be announced at 2pm.
The list will be notable for the absence or otherwise of Kevin Pietersen, whose on-off limited-overs retirement will probably depend on whether he can reach a compromise deal with the England and Wales Cricket Board in time to play in the World Twenty20 in Sri Lanka in September.
Captain Andrew Strauss has reiterated England are fully focused on beating South Africa.
Suggestions have been made that Kevin Pietersen's high-profile limited overs retirement has been an unwelcome distraction as England bid to defend their place at the top of the International Cricket Council Test rankings.
However, Strauss has refuted claims the situation has affected morale in England's camp ahead of the first Test tomorrow.
"The conversations that Kevin's been having are between himself and his representatives on the board," Strauss said on Sky Sports News.
"The players haven't been involved, the management haven't been involved and that's the way we'd like it to remain.
"It hasn't been a distraction to us, it's something that hasn't entered our thinking and it's allowed us to concentrate properly on this game.
"Kevin as much as anyone is determined to do well in this series and I haven't seen any signs in his preparation to suggest he's in any way distracted by what's going on."