Arsenal are set to face Manchester United in a pre-season clash at the SoFi Stadium in Los Angeles, and Leandro Trossard is in line to start. The Belgian appeared off the bench in Arsenal’s opening match with Bournemouth, but was clearly way off the pace as he sent a shot at goalkeeper Neto, before then missing his penalty in the shootout which followed. Trossard scored 17 goals in all competitions last season, and proved to be a clutch figure in key moments for Arsenal. Despite this, the 29-year-old still has a lot to prove to Mikel Arteta. The attacker suffered a particularly disappointing E…