Arsenal are without Petr Cech and David Ospina, so 24-year-old Martinez makes his first Premier League start of the season.
Aaron Ramsey and Alex Oxlade-Chamberlain are only fit enough for the bench.
For West Ham, Andy Carroll leads the line while Diafra Sakho is fit enough for a spot on the bench.
Elsewhere Michail Antonio returns to the starting line-up.
ARSENAL: Martinez, Bellerin, Mustafi, Gabriel, Monreal, Elneny, Xhaka, Walcott, Ozil, Alexis, Welbeck.
Read the full article on eurosport.co.uk: Martinez starts for Arsenal, Carroll leads West Ham line