James Anderson is in doubt for the first Test between England and South Africa in Durban due to a calf problem.
England's key seam bowler managed to get through only five overs of the tour match against a South African Invitational XI in Potchefstroom this month.
He reported tightness in the calf muscle of his right leg on Monday and underwent scans on Tuesday, leaving head coach Trevor Bayliss and the tourists sweating on the fitness of the 33-year-old.
"Unfortunately Jimmy's had a little bit of a tight calf muscle," Bayliss said.
"We're just waiting on some test results there and hopefully we'll know in the next day or two.
"It's a concern. He hasn't been able to bowl a lot of overs on this tour... he has bowled overs though so whatever it is it's not a terribly bad one."
Anderson, England's leading wicket-taker with 426 scalps in the long form of the game, will make his 111th Test appearance should he be passed fit to play in the first match at Kingsmead, which starts on Saturday.
England's other pace bowlers on the tour, Stuart Broad, Steven Finn, Chris Jordan, Chris Woakes and Mark Footitt - the latter seeking to make his Test debut - are all available.