Espinoza turned pro in 1982 and won the Vacant WBA Super Bantamweight Title in 1987 by defeating Tommy Valoy, becoming the first world champion boxer from Arizona in history. He defended the title twice before losing it to Julio Gervacio later that year. In 1989 he took on IBF Featherweight Title holder Jorge Páez but came up short in a draw. He won the WBO Featherweight Title later that year by beating Maurizio Stecca by TKO, but lost the belt the following year in a close decision loss in a rematch with Páez.