By Mitch Wilks Arsenal midfielder Granit Xhaka had to be substituted just 15 minutes into their clash with Wolves on Saturday evening, sparking fears with the World Cup around the corner. The Switzerland international has enjoyed an exceptional start to the season and become one of Arsenal’s key players as they sit top of the Premier League, but didn’t look at his best in the opening stages. Mikel Arteta called on Mohamed Elneny and Fabio Vieira to begin warming up mere minutes into the match, but Xhaka continued for as long as he could. He was substituted after 15 minutes though and replaced …