next round. However, Reginiussen suffered a muscle injury and had to be substituted in the first half during a 2–1 loss against Aalborg on 13 August 2011. It wasn't until on 23 August 2011 when he made his return to the starting line-up, as OB lost 3–0 against Villarreal, losing 3–1 on aggregate of the UEFA Champions League Play–Off Round and was eliminated from the tournament. Reginiussen scored his second goal for the club, in a 3–1 win against Wisła Kraków in the UEFA Europa League Group Stage. After missing one match, due to a finger injury, he scored on his return to the starting line-up, in a 3–1 loss against FC Midtjylland on 26 November 2011. Reginiussen later scored again on 25 March 2012, in a 4–2 loss against HB Køge. However, he suffered a leg during a match against FC Midtjylland on 14 April 2012, leading him to be sidelined for the rest of the season. Having established himself in the starting eleven at OB, Reginiussen went on to make thirty appearances and scoring three times in all competitions, At the start of the 2012–13 season, Reginiussen saw his first team opportunities at OB limited in his second season, appearing as a late substitute in the first two league matches. Rosenborg On 5 August 2012, Reginiussen signed a three-and-a-half-year deal with Norwegian team Rosenborg. Reginiussen made his Rosenborg debut, starting the whole game, in a 3–0 win against Sogndal IL on 12 August 2012. He then played in both legs of the UEFA Europa League Qualifiying Round against Legia Warsaw, scoring in the second leg in a 2–1 victory, and ultimately progress through to the group stage following a 3–2 win on aggregate. Since joining the club, Reginiussen became a first team regular for the side, playing in the centre–back position and formed a partnership with Stefan Strandberg. Having helped the side keep three clean sheets throughout the 2012 season, he went on to make seventeen appearances and scoring once in all competitions. Ahead of the 2013 season, Reginiussen was chosen by the new head coach Per Joar Hansen as Rosenborg's captain, replacing Mikael Dorsin. He started the season well as captain by helping the club keep a clean sheet in the first three league matches of the season. Reginiussen started the first seven matches until he was sent off in the 65th minute for a professional foul