Toby Roland-Jones
Age: 29
First-class bowling average: 25.73
First-class batting average: 22.56

"He's a traditional English seamer," says his county director of cricket (and England selector) Angus Fraser. "He's tall, accurate and he hits the pitch hard. He's not the quickest, but nor is Philander and nor were Pollock or McGrath. I suppose he is a bit like I was."

One of the most consistent seamers in the England game over recent years, Roland-Jones has claimed 271 first-class wickets since the start of the 2012 season at a cost of 26.66 apiece. Bearing in mind he has played more than a third of those games on an often unforgiving Lord's surface and those are impressive figures.

Having started out as a batsman - "he set records in colts cricket," Fraser says - he drifted out of the Middlesex system and onto university.

Given a second chance with Leeds-Bradford MCCU, he gained from a growth spurt that made him a far tougher proposition as a bowler and, having trailed with both Middlesex and Surrey, was given another opportunity with Middlesex. In contrast to Mark Wood, who he replaces, he generates decent but far from explosive pace from a long run and a high action. He generally tries to hit the seam and nibble the ball either way, but he can gain a little swing (generally away from the right-hander), too. He remains an attractive, aggressive batsman, with an average in the mid-20s but can be expected to bat at No. 9 in the England order.

He is probably best known for taking a hat-trick that secure the County Championship title at the end of the 2016 season, but he made his England ODI debut on his home ground of Lord's earlier this season and, having recorded the second-highest score of the England innings with an unbeaten 37 claimed Hashim Amla as his maiden international wicket.

Tom Westley
Age: 28
First-class batting average: 37.44
First-class bowling average: 46.45

A century against an Australia side containing Starc, Hazlewood et al. ahead of the 2015 Ashes marked Westley out as one for the selectors to keep their eyes upon. That he followed it with centuries against the Sri Lanka tourists in 2016 and South Africa in 2017 (he was representing the Lions on that occasion) suggested it was no fluke. Especially good off his legs, Westley has found a new level of consistency over the last couple of years

If there are concerns, they come in his relatively limited experience in Division One of the Championship. Just three of his first-class centuries have come at that level (two this year and one in 2010) with a suggestion from some in the domestic game that he is not the most comfortable against the short ball likely to be examined by the South Africa attack. But he has a strong record for the Lions - he averages 68.16 for them in first-class cricket - and has looked very much at home at the higher level this year. He is averaging 56.18 in first-class cricket this season.

"He's scored runs against international sides," says his new captain, Joe Root. "He's been in the Lions for a long time and he's been a consistent performer. He's had a strong start to the year and he has a very strong leg-side game in particular."

As a right-handed batsman, he will break-up a top three that was exclusively left-handed in the first two Tests and is also a tidy offspinner, which could come in useful if Liam Dawson is omitted. Like Roland-Jones, he graduated through the MCCU system - a system that's future is in doubt as the ECB review its status - and captained both Durham MCCU and England Under-19s. He is only the second England player this century (after Owais Shah in 2006) to make his Test debut at No. 3.

Dawid Malan Age: 29
First-class batting average: 38.09
First-class bowling average: 39.32

Malan's progress as a Test proposition probably owes a disproportionate amount to one T20 innings. On his international debut in June, he made 78 against South Africa, taking the Man of the Match award and making a strong impression upon the coach, Trevor Bayliss, with both his talent and temperament.

In truth, he had been pushing for selection for some time. He made a record-breaking score of 185 for the Lions against Sri Lanka A in 2016 and, since the start of 2014, has added consistency to a game that has never suffered for a lack of flair. He contributed three centuries as Middlesex won the Championship in 2016 and, while he was still thought more likely to win an international call-up as a white-ball player, built on a solid 2015 when he averaged a fraction under 50 in first-class cricket.

Born in England but brought-up in South Africa, Malan made his first-class debut for Boland. But after just four first-class games for them, he moved to England and made a century on first-class debut for his new club, Middlesex. An elegant left-hander, Malan looks comfortable against the short ball and, over the last couple of years, has tightened up considerably outside off stump. If he plays - and it will come down to a decision by the captain and head coach on Thursday morning after a look at the pitch - he will bat at No. 5. He also bowls good enough leg-breaks to have taken a first-class five-for.

"He's a very elegant player with a nice range of strokes," Fraser says. "He record over the last two-and-a-half years, when he has been playing at the top of Division One, is very good.

George Dobell is a senior correspondent at ESPNcricinfo