Tokushima Vortis
Kozuka joined Albirex Niigata as an apprentice professional in 2012. He turned full-time professional with Albirex at the start of the 2013 season and made his first-team debut against Tokushima Vortis in the first round of the Nabisco Cup. His first J. League appearance was in the 2–1 away win over Tokushima Vortis on 26 April 2014.