Manager Arsene Wenger has opted to switch to a 3-4-3 system, with Laurent Koscielny returning from injury to play alongside Gabriel and Rob Holding.
Olivier Giroud is also recalled, with Theo Walcott joining Bellerin among the substitutes.
Petr Cech, Aaron Ramsey and Alex Oxlade-Chamberlain are also included from the start as the Gunners make six changes from their defeat to Crystal Palace last time out.
Shkodran Mustafi (thigh) misses out through injury as does forward Danny Welbeck (toe).
Middlesbrough: Guzan; Barragan, Ayala, Gibson, Fabio; Clayton, De Roon, Leadbitter; Ramirez, Downing, Negredo.
Bench: Dimi, Friend, Bernardo, Forshaw, Traore, Bamford, Gestede
Arsenal: Cech; Gabriel, Koscielny, Holding; Oxlade-Chamberlain, Ramsey, Xhaka, Monreal; Ozil, Alexis; Giroud.
Bench: Martinez, Bellerin, Gibbs, Coquelin, Elneny, Walcott, Iwobi