The Reds did not tender a contract to Billy Hamilton:

Arguably the biggest name on the list, Billy Hamilton has game-breaking speed and can run down just about anything in center field. Unfortunately, he can’t hit. Hamilton finished with an OPS+ below 70 for a second consecutive season in 2018, and hasn’t so much as topped 80 since his rookie season in 2014. His wheels and glove are certain to land him another gig. The question is if his next employer will figure out a way to better improve or hide his shortcomings.

He would likely fit best on a team with a very good offense and a fly ball pitching staff. One has to believe that the Reds pitching staff probably looks a lot worse without Hamilton in centerfield.