At the start of the 2002–03 campaign, Arca continued to recover from his injuries he sustained from the previous season. His first appearance of the season came on 28 August 2002, coming on as a late substitute, in a 1–0 win over Leeds United. Arca, who had then played 54 games for the club, stated his determination to get back to his best – both in fitness and form, especially playing under the management of Reid's successor, Howard Wilkinson. Due to being a fan favourite among Sunderland supporters, they chanted "Julio, Julio" when he was not in the squad. Despite this, Arca scored his first goal of the season, in the second round of the League Cup, in a 2–0 win over Cambridge United on 1 October 2002. He was sidelined for two months, due to an injury he sustained during the club's reserve match against Manchester United Reserve. After returning from injury in December, Arca didn't make his return to the first team until on 11 January 2003, coming on as a second–half substitute, in a 0–0 draw against Blackburn Rovers. Three days later on 14 January 2003, he scored his second goal of the season, in a 2–0 win over Bolton Wanderers in the FA Cup replay. Since returning to the first team, Arca had a run in of first team for the rest of the season despite being on the sidelined on three occasions. At the end of the 2002–03 season, the club was relegated to the Championship, finishing at the bottom of the Premier League, and he went on to make eighteen appearances and scoring two times in all competitions.