What about Navas and Cazorla for a season, Both may be available on a free transfer as possible squad players
Navas has done nothing of note in years now and wouldd be a poor addition in my opinion. He has one assist every 5 games in teh Premier League, which while not terrible, isn't great for a team like Man City. He's also only scored 4 Premier League goals for City in 125 appearances (or 81 sets of 90 minutes), a poor return. Then add high wages and age and he's not a great option.
As for Cazorla, I've always been a big fan, I've been to the Emirates with my mates to watch Arsenal a few times over the past few years and along with Sanchez he was the stand out performer. He's a delight to watch. But again age and wages come into it. Also, does he fit Koeman's style? Is he going to work hard enough? Will be able to last 90 minutes anymore? I'm not convinved it would be a good signing, a couple of years ago maybe. At 32 he would need to be a quick fix and I don't believe he would make a big enough difference to our squad.