At the start of the 2005–06 season, with Sunderland back in the Premier League, Arca continued to remain as first team regular, playing in the left–back position. However, the club made a poor start to the season, losing the first five league matches. He then scored his first goal of the season, in a 2–0 win over Middlesbrough, giving Sunderland their first Premier League since 2002. However, Arca suffered a toe injury during training and missed two matches. It wasn't until on 23 October 2005 when he returned to the first team, coming on as a second–half substitute, in a 3–2 loss against rivals, Newcastle United. His return was short–lived when he once again injured his toe after the match and was sidelined for a month. It wasn't until on 10 December 2005 when Arca returned to the starting line-up, playing the whole game, in a 2–0 loss against Charlton Athletic. Since returning to the first team, he quickly regained his place in the starting eleven, playing either the left–back position or midfield position over the season. In the January transfer window, Arca was linked a move away from the club, which he responded by stating that he has no intention of leaving Sunderland. Amid to the transfer move, Arca then scored his second goal of the season, in a 2–1 loss against Brentford in the fourth round of the FA Cup. During a 4–1 loss against rivals Newcastle United on 17 April 2006, he collided with Alan Shearer, resulting in him tearing his knee injury. However, he suffered injuries on three occasions later in the 2005–06 season. Sunderland were relegated again in the 2005–06 season. At the end of the season, Arca went on to make twenty–six appearances and scoring two times in all competitions.