It is widely assumed that once the transfer window is shut then that is the end of any further business until January but that is not actually the case.
Clubs can still sign a player provided that he is out of contract and that they became out of contract prior to the transfer deadline.
So, for example, Memphis Depay could yet be snapped up or Ross Barkley. Now, I am not suggesting for one second that Arsenal sign either of those two, they are purely examples.
The Daily Express listed a number of players that are currently available, seven in fact, however, there are many others that are no longer on a contract and that means that Arsenal may yet bring a new player in.
Whether there are any that suit Arsenal is open to question but considering that we still need a number of positions strengthened, midfield, for example, then the option is certainly there, especially if Thomas Partey is out longer than we expect.
It is probably unlikely that Arsenal will dip back into the market but you never know, stranger things have happened in football in the past.