David Toussaint beat Shane Mosley Jr. then out of left field retires due to some Head injury. Any other examples?
Do you mean retiring after a fight where they won? coz if you just mean them retiring because they were hurt they are plenty of examples even just recently: Blackwell, Gutkneckt, Skoglund, Stevenson.
Zack Padilla. I think it was an injury in sparring from young Shane Mosely. Too bad, because Padilla was basically at the zenith of his career and after big wins over Carlos Gonzalez, Roger Mayweather, Ray Oliviera, and Juan LaPorte, he was finally at a point where he might start making some serious dough.
Joe Mesi did after the Jirov fight. Came back and had some low level fights years after so not sure that example counts
It makes sense imo He was in some Absolute barn burner Grueling Fights. Respect to him He was likely getting paid peanuts for going to hell & back. Modern day gladiator