The England international gets the nod after finding himself on the substitutes' bench in recent weeks, while the Brazilian is dropped in favour of Laurent Koscielny
The England international has found himself out of favour at the Emirates this season, but after scoring a hat-trick against Reading in the League Cup, finds himself included in tonight's team.
As revealed by Goal.com earlier on Tuesday, Santos, who raised controversy with his decision to swap shirts with Robin van Persie at half-time during their 2-1 defeat at Manchester United on Saturday, finds himself relegated to the bench, with boss Arsene Wenger reportedly looking to offload him in January.
The Brazilian is replaced by Laurent Koscielny, with Vermaelen likely to play at left-back.
The only change for Schalke since the last time these two sides met is 31-year-old Jermain Jones coming in to centre midfield in place of Marco Hoger.
Schalke: Unnerstall; Uchida, Howedes, Matip, Fuchs; Jones, Neustadter; Farfan, Holtby, Afellay; Huntelaar
Subs: Hildebrand, K Papadopoulos, Kolasinac, Hoger, Moritz, Draxler, Marica
Arsenal: Mannone, Sagna, Mertesacker, Koscielny, Vermaelen; Arteta, Wilshere; Walcott, Cazorla, Podolski; Giroud.
Subs: Shea, Santos, Djourou, Jenkinson, Coquelin, Arshavin, Chamakh