England are "holding their breath" over James Anderson's latest injury.
Anderson, who took seven wickets in England's second Test win against South Africa, is to undergo scans on a side injury after struggling through the fifth day at Newlands.
"He's been such a great servant that we're holding our breath and (have) fingers crossed for him," Ashley Giles, director of England men's cricket, told BBC Radio 5Live.
"We'll be desperate if Jim was injured again. He's worked so hard to get back in the team.
"He bowled like a demon in that first innings and that mix of youth and experience we have in the team is just so valuable.
"We certainly don't think it's a recurrence of his previous injury."
Anderson has just returned from a five-month lay-off with a calf problem.
The 37-year-old, England's record wicket-taker in Test cricket, was visibly labouring as the game reached its conclusion.
Anderson spent time off the field in the middle session and managed just two overs after tea.
He grimaced through those, although he remained involved and took a key catch at leg-slip to dismiss Rassie Van Der Dussen.
England captain Joe Root, speaking after his side had levelled the four-match series in Cape Town, said Anderson's fitness was a waiting game.
"He'll go for a scan, get some treatment and we'll see how he pulls up going into the next Test in Port Elizabeth," said Root.
"It's his side, but it could be just a little niggle. It could be a 24 to 48-hour thing or it could be something else.
"Until we have more information we'll just treat it as best we can and fingers crossed he's not another casualty of this tour."
Opener Rory Burns flew home after injuring his left ankle playing football on the eve of the game and has now been ruled out for four months.
