Three Saints stars are in the England squad to face Wales at Twickenham on Sunday (kick-off 2pm).
Courtney Lawes, uncapped Lewis Ludlam and Piers Francis are all part of the group that has assembled at Pennyhill Park ahead of the World Cup warm-up match.
With no new players added to the squad following England’s 12-day training camp in Italy, Mike Brown, Alex Dombrandt, Ben Spencer and Ben Te’o are not included in this week’s squad.
In addition, Exeter Chiefs ace Jack Nowell will continue his rehabilitation in camp.
England boss Eddie Jones said: “We have worked hard and now move into a four-game preparation phase where the development of the team tactically is paramount.
"We are grateful for the strong opposition to test our game fitness.
“By the time we fly out (to Japan) on September 8 we will be ready to win the Rugby World Cup.
"We are not there yet but we have four games to get ready.
“Players excluded from being involved in this camp are naturally disappointed but may get another opportunity so they must be ready."
Following the game against Wales, England face Ireland (August 24) at Twickenham Stadium and Italy (September 6) in Newcastle as part of the Quilter Internationals.
They will also travel to Wales for a fixture in Cardiff, on August 17.
England will begin their Rugby World Cup campaign in Japan against Tonga in Sapporo (September 22, KO 11:15am UK time) before playing USA in Kobe (September 26, KO 11:45am UK time), Argentina in Tokyo (October 5, KO 09:00am UK time) and France in Yokohama (October 12, KO 09:15am UK time).
England squad to face Wales
Dan Cole (Leicester Tigers, 85 caps)
Luke Cowan-Dickie (Exeter Chiefs, 11 caps)
Tom Curry (Sale Sharks, 10 caps)
Charlie Ewels (Bath Rugby, 10 caps)
Ellis Genge (Leicester Tigers, 9 caps)
Jamie George (Saracens, 37 caps)
Maro Itoje (Saracens, 27 caps)
George Kruis (Saracens, 32 caps)
Joe Launchbury (Wasps, 58 caps)
Courtney Lawes (Saints, 71 caps)
Lewis Ludlam (Saints, uncapped)
Joe Marler (Harlequins, 59 caps)
Kyle Sinckler (Harlequins, 22 caps)
Jack Singleton (Saracens, uncapped)
Sam Underhill (Bath Rugby, 9 caps)
Billy Vunipola (Saracens, 41 caps)
Mako Vunipola (Saracens, 53 caps)
Harry Williams (Exeter Chiefs, 17 caps)
Mark Wilson (Newcastle Falcons / Sale Sharks, 13 caps)
Joe Cokanasiga (Bath Rugby, 4 caps)
Elliot Daly (Saracens, 30 caps)
Owen Farrell (Saracens, 70 caps)
George Ford (Leicester Tigers, 55 caps)
Piers Francis (Saints, 4 caps)
Willi Heinz (Gloucester Rugby, uncapped)
Jonathan Joseph (Bath Rugby, 40 caps)
Joe Marchant (Harlequins, uncapped)
Jonny May (Leicester Tigers, 45 caps)
Ruaridh McConnochie (Bath Rugby, uncapped)
Henry Slade (Exeter Chiefs, 22 caps)
Manu Tuilagi (Leicester Tigers, 32 caps)
Anthony Watson (Bath Rugby, 33 caps)
Ben Youngs (Leicester Tigers, 85 caps)
Jack Nowell (Exeter Chiefs, 33 caps)