Rutgers football player Peyton Powell says he's transferring ... claiming it's all 'cause the university has made it mandatory for students to get the COVID vaccine.

The school announced back in March if students wanted to attend classes and play football for the university, they'd have to get the shots.

"We are committed to health and safety for all members of our community," Rutgers president Jonathan Holloway said when announcing the decision.

"Adding COVID-19 vaccination to our student immunization requirements will help provide a safer and more robust college experience for our students."

Powell says after considering the school's choice ... he's now decided to leave the university in search of one that will not make the vaccine mandatory.