Arsenal announced defender Hector Bellerin suffered an injury on Monday in the warm-up before his team's clash with West Ham United at the London Stadium.
Interim manager Freddie Ljungberg named Ainsley Maitland-Niles to start in Bellerin's place and the Gunners added Sead Kolasinac to the bench for the match.
Bellerin recently returned to the first-team picture after a cruciate knee ligament injury picked up in a 2-2 draw with Chelsea in January kept him sidelined for nine months.
While Arsenal are blessed with depth in their squad in a number of areas, Bellerin is one of a few players who are indispensable.