Arsenal manager Mikel Arteta has confirmed Thomas Partey suffered an injury in the 3-0 loss to Aston Villa on Sunday.
The Ghana midfielder was brought off at half-time for Dani Ceballos.
And Arteta says the change was not tactical.
"Thomas Partey is injured," Arteta said when assessing his team's performance after the game.
"I support the five substitutes rule but I'm also for the possibility of having 20 players in the squad, but that's another story that we can not control."
