School officials announced Wednesday that the NCAA had granted a waiver for Reitmaier.
Reitmaier, who is from Nashville, initially signed with Oregon and participated in the Ducks' 2017 spring practice. He left Oregon after spring practice and sat out the 2017 season but didn't enroll at Vanderbilt until January 2018.
He participated in Vanderbilt's 2018 spring practice.
"Adding Rutger to our roster is huge," Vanderbilt coach Derek Mason said. "He adds depth, athleticism and will be a key piece for us. I'm excited about what an impactful player he is, and it's great to add another quality player from Nashville."