Arsenal manager, Mikel Arteta, has admitted that he does not know why Bukayo Saka needed to be substituted during their 1-0 win to Tottenham on Sunday. Saka asked to be taken off before the end of the game and was subbed off in the 86th minute. Arteta replaced the England winger with youngster Ethan Nwaneri. With Martin Odegaard also out injured, Arsenal will be hoping that Saka’s injury is merely trivial. The 23-year-old has provided an assist in every Premier League fixture he has played this campaign and has one goal to his name. The Gunners are away to champions Manchester City next Sunday…