Alexis Sanchez is expected to undergo a medical at Carrington on Sunday before being announced as a Manchester United player on Monday. Apart from his undeniable quality, one of the more alluring aspects of the 29-year-old's signature is the fact that he can play continental football for the Red Devils.
After Arsenal finished fifth last season, the Chilean was made to settle for the Europa League in the first half of the season, while in the second he will be eligible to play in the Champions League once he completes his transfer to Manchester United.
A similar situation for Henrikh Mkhitaryan if the proposed swap deal between the two players is concluded. The Armenian will also be available to play in the Europa League for Arsenal despite featuring for United in the Champions League.
Arsenal have also made an enquiry about Borussia Dortmund striker Pierre-Emerick Aubameyang who, if he completes the reported £50m switch to the Emirates this window, would not be available to Arsene Wenger to play in the Europa League.
While Sanchez has already played in the Europa League for Arsenal this season, rules clear Sanchez to play in the Champions League as it is different to the competition the Gunners are currently a part of. The same rules apply for Mkhitaryan.
UEFA rules state that new signings are unavailable if they have played in the same European competition for a different club, or if they have played for a club that are currently in the same European competition as their new club.
This means that Dortmund's future involvement in the Europa League after finishing third in their Champions League group makes Aubameyang ineligible to play for any other club in the competition this season, despite the fact their first Europa League game is next month.