Angelidis spent his entire OHL career with the Owen Sound Attack, but he went undrafted when he was eligible due to a 17, 18, and 19 points in his first three seasons beginning in 2002-03. However, Angelidis was always a physical player who dropped the gloves fairly often.
In 2005-06 he put the physical part of his game together with some scoring and finished third on the team in total points, with 78 in 68 games. He saw regular powerplay time and played along side Anaheim prospect Bobby Ryan quite often.
A junior career highlight for Angelidis occured on March 4, 2006, in his fifth to final OHL regular season contest. In that game against the Guelph Storm, Angelidis had four goals, including a natural hatrick and two powerplay markers. Angelidis was named a first-team All-Star in the OHL in 2006, as well as winning the Dan Snyder Humanitarian of the Year award due to his various contributions to the community. As a result of the strong showing in his final year in the OHL, the Hurricanes signed the 21-year-old as a Free Agent on July 21, 2006.
2007-08: Angelidis had a solid first full season with Albany, accumulating 27 points on 11 goals and 16 assists in 74 regular season games. He was also second on the River Rats in penalty minutes with 151. He added two assists in seven postseason games.