The involvement of Aaron Ramsey, Mesut Özil, Laurent Koscielny and Olivier Giroud in the beginning of the season is doubtful, after Arsène Wenger confirmed that those four players, all of whom played in the latter stages of the European Championship, will need four weeks holiday before returning to training. That means Giroud and Koscielny won't return until around August 8, while semi-finalists Özil and Ramsey will return the previous week. With the first match of the season August 14, and everyone likely needing around two weeks of training to return, it is likely that all four will miss the opening match of the season against Liverpool, and quite possibly the second match of the season, away at champions Leicester.
Hopefully Wenger has learned from two years ago, when he brought back Per Mertesacker and Özil far too quickly after the summer, and both suffered middling form. Alexis Sánchez was also brought back quickly last season after Copa America, and had a fairly average beginning to the season before succumbing to injury.