The versatile Helena Rowland starts for the first time on the wing having previously covered the position from the bench. Jess Breach is on the other with Emma Sing continuing at full-back.
Zoe Aldcroft, Sadia Kabeya, Holly Aitchison and Abby Dow are among the replacements.
England’s meeting with Spain, ranked 13th in the world, is the first of two warm-up matches for the World Cup.
They will also take on France away next weekend in Mont-de-Marsan, when Mitchell is likely to field something close to a first-choice team.
England’s formidable strength in depth – with players honed in England’s world-leading PWR competition – could be a key part of their campaign.
They take on the United States in the tournament opener in Sunderland on 22 August.
England: Sing; Rowland, Jones, Shekells, Breach; Harrison, L Packer; Clifford, Atkin-Davies, Bern, Galligan, Campion, Burton, M Packer (capt) Feaunati.
Replacements: Campbell, Botterman, Muir, Aldcroft, Kabeya, Hunt, Aitchison, Dow
