Has been out injured since December
©IMAGO
Mainz 05 will loan Kasey Bos to Dutch first division club Excelsior Rotterdam next season. The 22-year-old left-back is expected to gain match practice in the Eredivisie. There he will meet his brother Jordan Bos in the derby, who is a top performer at local rivals Feyenoord Rotterdam.
“It’s important for Kasey that he gets playing minutes at the highest level – at Excelsior Rotterdam he has the opportunity to develop further in a top league. Excelsior Rotterdam is the ideal club for this. In addition, being close to his brother Jordan, who already plays an outstanding role at Feyenoord Rotterdam, will certainly help him get used to a new city,” said sports director Niko Bungert.
Bos came to Mainz from Melbourne Victory in the summer of 2025 for 500,000 euros. In the past season he was used 14 times for the U23s in the Regionalliga West, but he was not on the pitch for the professionals. He has been out since the beginning of December with a shoulder injury. His new club Excelsior Rotterdam ended the season in 13th place in the Eredivisie.