Arnold started his revamp of the squad by releasing 13 players in the pre-season. To solve the teams goalscoring issues, he bought in Brazilian striker Bobô as their new marquee to play alongside former teammate Filip Hološko under the new 2 marquee rule. In addition to this, he also brought in 5 Australian players, including Bernie Ibini on loan, Socceroo Alex Wilkinson (two whom have worked with Arnold at the Central Coast) and Danny Vukovic from rival club Melbourne Victory. The season started off with a bang, with Sydney FC defeating their rivals Western Sydney Wanderers 4–0 in round 1. He led the team to a runners-up finish after being defeated 1–0 in the FFA Cup Final by Melbourne City.