Warnock is hoping to play some part in Sunday's friendly against Japan in Graz in order to press his claims for a place in the 23-man squad that Fabio Capello will unveil on June 1.
However, Warnock will now need to be assessed before it is known whether he will be able to resume training tomorrow.
Although he was rated an outsider to go to South Africa, Leighton Baines' modest display against Mexico on Monday night meant Warnock was still in with a chance of being named as back-up to first choice left-back Ashley Cole.
Sources close to the England camp also played down speculation that Steven Gerrard had limped out.
The Liverpool skipper is clearly a key part of Fabio Capello's plans and did stop training today to do some stretching exercises.
However, he was able to complete the session and is expected to be involved against Japan, who were beaten on home soil by South Korean earlier this week.
Happily for Darren Bent, the Sunderland man has also shrugged off the hamstring problem that prevented him from facing the Mexicans and is also in contention for the weekend.
Capello has already confirmed Ledley King will not take part, whilst the Chelsea contingent of John Terry, Frank Lampard and Cole will play, although the presence of Joe Cole in the Italian's starting line-up is less certain.