Reds:
Joey Jay (76) -Made his major league debut at age 17 due to the old "bonus baby" rule (players who signed for over a certain amount had to be immediately put on the ML roster). Had back-to-back 21-win seasons for the Reds in '61 and '62. Posessor of two of baseball's most impressive eyebrows (or one if you consider it a unibrow...)
Others:
Oliver Perez (30) -Should still be in the middle of his career; instead he's pretty much toast. Hard to imagine him getting even a spring training invite unless he goes to the Mexican League and lights it up or something.
Chris Singleton (39)
Jeff Huson (47) -Harder to get rid of than nail fungus, this utility infielder hung around for 12 years despite a career OPS under .600.
Duffy Dyer (66) -Backup catcher to Jerry Grote in New York and Manny Sanguillen in Pittsburgh. Good glove man; later spent seven seasons coaching 3B in Milwaukee. As of 2008 he was the minor league catching coordinator for the Padres, but he may have retired.
Charles Comiskey- Everybody knows he was a horrible human being, but they keep naming stadiums after him...