Mikel Arteta has confirmed the unusual pattern of injuries is being examined internally. "It's very unusual," the manager said. "It probably happened once or twice in six years I've been here and it's happened four times this season."
The most recent case involved Riccardo Calafiori, who was withdrawn before the game against Wigan, forcing changes across the side. Earlier in the campaign, William Saliba and Bukayo Saka also suffered warm-up injuries.