Arsenal forward Alexis Sanchez will miss the start of the season after helping Chile win the Copa America. The 26-year-old scored 25 goals for the Gunners last season as Arsene Wenger’s side finished third in the Premier League, and added a stunning goal as they won the FA Cup. Wenger said: “Alexis will be back with us on 3 August and usually it takes three weeks to be competitive. “With Alexis it could be a bit less. He will miss certainly the first game.” Sanchez will miss the Community Shield against Chelsea on 2 August. The Gunners open their Premier League campaign against West Ham on Sunday, 9 August, and if Sanchez did need a full three weeks to be match fit he could also miss games against Crystal Palace and Liverpool. Sanchez scored the winning penalty as hosts Chile won their first Copa title against Argentina on 4 July – the end of a 58-game season for the former Barcelona forward. Manchester City defenders Pablo Zabaleta and Martin Demichelis and Manchester United pair Angel Di Maria and Marcos Rojo all played for Argentina in that final. Tottenham winger Erik Lamela was an unused substitute.