Kasey Bos will play for Excelsior on loan from FSV Mainz for the next season, a move announced on the Rotterdam club's official channels. Bos moved to Mainz last summer from Melbourne and has not yet made his official debut for the first team, partly due to a shoulder injury. Excelsior's technical director, Mark Ruijl, revealed the club was looking for a new left-back, and Bos stated that he feels the move is a good step for his career.