Marchant will win his third cap in tomorrow night’s final warm-up Test before Japan 2019 as part of a centre partnership alongside Piers Francis.
The Harlequins back was omitted from the 31 selected for the World Cup but, with Slade and Joseph receiving treatment, head coach Eddie Jones has opted against exposing Manu Tuilagi to the risk of injury at St James’ Park.
Instead, in comes Marchant who has been training with England for much of the summer and has been a part of the second camp in Treviso, north-east Italy.
It was hoped that Slade would make his comeback from a knee problem against Italy, having missed the previous three games of the summer, while Joseph was withdrawn from the rout of Ireland because of a leg muscle issue.
“Henry is doing really well. He was running (on Tuesday),” forwards coach Steve Borthwick said.
“It’s just a case of that next stage, that last stage. He’s just not quite ready for this game, but he’s close.
“Jonathan is also close. He’ll be in full training (on Thursday). He’s not quite ready for this game. A muscle in his leg has needed some load management.
“But great credit to Joe Marchant. The weeks he has trained with us he’s been absolutely outstanding. His attitude has been first class and he has improved every training session.
“It’s been a great opportunity for us. We’ve talked all along about having that four-game plan and being able to adapt.
“Clearly there has been some need for adaptation, but this is a great opportunity because we’ve been able to use different combinations again.”
Slade’s absence means he will enter the World Cup having not played a single minute of rugby since the Gallagher Premiership final at the start of June.
It is a fate shared by his Exeter colleague Jack Nowell, whose ongoing ankle problem has been compounded by last week’s emergency operation to have his appendix removed.
Two additional players not picked for the World Cup are present on the bench in lock Charlie Ewels and flanker Matt Kvesic.
Ruaridh McConnochie finally makes his debut on the right wing after two aborted attempts in the double header against Wales due to hip and hamstring injuries. The Bath sevens specialist forms a rapid back three alongside Anthony Watson, who makes his fourth appearance at full-back, and Leicester flyer Jonny May.
Jones has largely stuck to his tried and tested up front, including a fourth successive start for starNo 8 Billy Vunipola.
Mark Wilson, a Newcastle stalwart who will spend next season at Sale, makes his first start of the summer at openside flanker and Tom Curry is given another run at six.
England’s first outing at St James’ Park is two days before the squad set off for their training camp in Miyazaki.
England team: A Watson (Bath Rugby); R McConnochie (Bath Rugby), J Marchant (Harlequins), P Francis (Northampton), J May (Leicester), O Farrell (Saracens, captain), B Youngs (Leicester); J Marler (Harlequins), J George (Saracens), D Cole (Leicester), J Launchbury (Wasps), C Lawes (Northampton), T Curry (Sale), M Wilson (Newcastle), B Vunipola (Saracens). Replacements: L Cowan-Dickie (Exeter), E Genge (Leicester), K Sinckler (Harlequins), C Ewels (Bath Rugby), M Kvesic (Exeter), W Heinz (Gloucester), G Ford (Leicester), J Cokanasiga (Bath Rugby).