Atletico Madrid arrive at RCDE Stadium on a five-match winning run, 11 points clear of mid-table Espanyol in La Liga.
The Arsenal manager says reducing up to 60 roles is necessary to keep the club moving forward, but the timing alongside his own new contract has drawn scrutiny.
Second-half goals from Timber, Eze and Saka swept Arsenal past a stubborn Lille side who had kept them at bay for an hour.
The Argentine centre-back singled out technical director Jason Wilcox in a searing post-match television interview that drew an immediate rebuke from Wayne Rooney.
