3. Initial cover during adaptation

Zubimendi is not the only midfielder joining Arsenal this summer, with Brentford captain Christian Norgaard also bound for the Emirates Stadium. While the former is the big money spending among the pair, he may initially find himself as cover for this fellow new signing.
Joining from a La Liga side, the Spaniard could need a bit of time to adapt to the Premier League and that's where Norgaard comes in. The Denmark international has built up plenty of experience in England's top flight since first being promoted with the Bees and he would be capable of stepping in if needed.
It's unlikely Zubimendi will be utilised as cover after the club have spent big money on him, but if he does struggle initially, that could be the case. There would at least be a suitable candidate to replace him in the meantime, but I have no doubt that Zubimendi will be able to be an instant starter.