Eddie Jones has omitted Mike Brown, Ben Morgan and Michael Rhodes from his England squad to face South Africa on Saturday, with Courtney Lawes also ruled out through injury.

Bath’s Zach Mercer and Ben Moon of Exeter are in line to play in a Test for the first time, with the New Zealand-born back-row Brad Shields also on course for a Twickenham debut. Chris Ashton and Manu Tuilagi are poised for their first Test involvements since 2014 and 2016 respectively but there is no room for the 33-year-old Brown, who has never previously been dropped by Jones when fully fit.

The 72-cap Harlequins full-back played on the wing in all three summer Tests against the Springboks but he is among 10 players returning early from England’s training camp in Portugal.

Rhodes had also hoped to feature against his home country but, along with Lawes (back) and Maro Itoje, did not take a full part in training. The option of starting Itoje at No 6 and Shields at No 8 still remains open to Jones if he is concerned about throwing the 21-year-old Mercer straight in at the deep end for a Test debut in the absence of the injured Billy Vunipola.

Brown’s non-selection was half expected given Ashton’s return to the England fold but the decision to overlook the in-form Morgan – the most obvious like‑for‑like replacement for Vunipola – is a surprise.

The retention of Mark Wilson and Elliott Stooke in the 25-man squad may simply be precautionary but the Bath lock Charlie Ewels, 23, looks likely to secure his seventh cap. The 20‑year‑old Tom Curry is set to win only his fifth cap on the openside flank.

With the uncapped Moon and his club-mate Alec Hepburn included in the absence of the injured Mako Vunipola and Ellis Genge and the retired Joe Marler, there could be as few as three starting-forward survivors from England’s last Test when the team-sheet is confirmed on Thursday.

Behind the scrum there remains a decent chance of Owen Farrell starting at fly-half, possibly with Henry Slade and Tuilagi wearing 12 and 13 respectively.

Quick Guide England squad Show Forwards

Tom Curry (Sale Sharks), Charlie Ewels (Bath Rugby), Jamie George (Saracens), Dylan Hartley (Northampton Saints) co-captain, Alec Hepburn (Exeter Chiefs), Maro Itoje (Saracens), George Kruis (Saracens), Zach Mercer (Bath Rugby), Ben Moon (Exeter Chiefs), Brad Shields (Wasps), Kyle Sinckler (Harlequins), Elliott Stooke (Bath Rugby), Harry Williams (Exeter Chiefs), Mark Wilson (Newcastle Falcons) Backs

Chris Ashton (Sale Sharks), Danny Care (Harlequins), Elliot Daly (Wasps), Owen Farrell (Saracens) co-captain, George Ford (Leicester Tigers), Jonny May (Leicester Tigers), Jack Nowell (Exeter Chiefs), Henry Slade (Exeter Chiefs), Ben Te’o (Worcester Warriors), Manu Tuilagi (Leicester Tigers), Ben Youngs (Leicester Tigers).

Regardless of the starting lineup, England know they cannot afford to surrender the physical battle up front. “South Africa are such a physical team,” the Saracens hooker Jamie George said. “We’re aware our intent can never be questioned. We’re going to go out there and rip into it.”