Arsenal could be very busy in the final days of this summer transfer window. With Transfer Deadline Day arriving on Friday, time is running out for Mikel Arteta and Arsenal sporting director Edu Gaspar to complete the remaining business that they hope to conduct. Mikel Merino will join Arsenal very soon, as his switch from Real Sociedad is all but completed. Beyond the arrival of the Spanish midfielder, though, nothing is even close to certain when it comes to incomings or outgoings from the Emirates Stadium. Four Arsenal players could still leave, with Hale End academy duo Reiss Nelson and Ed…