Former England test captain Alec Stewart believes the form of Ravi Bopara will prove crucial in South Africa's attempts of becoming the world's No.1 test team.
Despite averaging just 34 with the bat in 12 test matches, Bopara has earned a recall after scoring 182 runs over four one-day internationals against Australia.
With Jonny Bairstow and Eoin Morgan both having missed their opportunities to become the long-term replacement for the retired Paul Collingwood, Stewart believes Bopara has an opportunity to stamp his mark on the middle order.
"All of England's batsmen are in good form but the man who might feel he still has questions to answer is Ravi Bopara," he said.
"Now fully fit, his excellent showing in the recent one-day series has rightly earned him a recall and I'm looking forward to seeing what the Essex man can do in the Test arena again.
"Bopara is a hugely talented individual, one that I'm a big fan of, but he hasn't shown yet on a consistent basis what he is really capable of in Test cricket.
"I hope he will be able to transfer what he's been doing in the shorter formats into the five-day game because, as well as his batting, a few overs of his medium pace could be very valuable.
"Since Paul Collingwood retired, a few players have been given the opportunity by England, but the likes of Eoin Morgan and Jonny Bairstow weren't quite able to cement their place at number six. Now it's up to Bopara to try to make it his own.
"The only way to do that is through sheer weight of runs."
South Africa have been forced into a reshuffle following injury and subsequent retirement of wicketkeeper Mark Boucher, with AB de Villiers likely to take the gloves for the four-match test series.
With a test average of close to 50 and 13 hundreds to his name, the onus will be on De Villiers to produce in both innings, and Stewart worries whether the responsibility will bring the best out of the 28 year old.
"AB de Villiers has kept wicket with style in the shorter forms of the game, but to date he has only donned the gloves in three Test matches," he added. "When it comes to keeping, there's a huge difference in doing it over five days compared to 50 or 20 overs.
"I'm also aware that keeping at times can cause him some back problems and he's inexperienced in English conditions. Because of his unbelievable natural sporting talent, I'm sure he'll do a more than decent job.
"The big question is what effect will keeping have on his batting? Without the gloves, I see him as one of the main dangermen in the tourists' line-up, but with the added responsibility of wearing the gloves, will that affect his run-scoring capabilities?"