England number eight Billy Vunipola says his prospects of playing at the World Cup are "positive" after undergoing knee surgery.

"I understand exactly what needs to be done over the next few weeks," he said.

Players from Sale and Saracens are also absent, while Beno Obano and Will Joseph are dropped.

Vunipola added: "The medical team are positive about my prospects."

Bath loose-head prop Obano and new Harlequins centre Joseph drop out as the squad is cut from 38 to 36 players.

Players from Saracens and Sale who featured in the Premiership final will be added to the training squad once their five-week rest period elapses at the end of this week.

Ollie Chessum, Luke Cowan-Dickie, Ollie Lawrence and Jack Walker remain in camp to continue their rehabilitation from injury.

England begin a four-Test summer series against Wales on 5 August and will also play Fiji and Ireland before their World Cup campaign gets under way with a Pool D meeting against Argentina in Marseille on 9 September.

England boss Steve Borthwick is due to announce his 33-man squad for the World Cup On 7 August.

The tournament, which will be hosted by France, starts on 8 September.

England squad

Forwards: Jamie Blamire, Dan Cole, Alex Dombrandt, Tom Dunn, Charlie Ewels, Ellis Genge, Joe Heyes, Ted Hill, Courtney Lawes, Lewis Ludlam, Joe Marler, George Martin, Zach Mercer, Tom Pearson, Val Rapava-Ruskin, David Ribbans, Kyle Sinckler, Will Stuart, Sam Underhill.

Backs: Henry Arundell, Danny Care, Joe Cokanasiga, Fraser Dingwall, Tommy Freeman, Joe Marchant, Jonny May, Alex Mitchell, Cadan Murley, Guy Porter, Henry Slade, Fin Smith, Marcus Smith, Freddie Steward, Jack van Poortvliet, Anthony Watson, Ben Youngs.