although the average MLB career is less than six years per a 2007 study 5.6 years 2007 study 5.6 years on average less than six years 5.6 years last only 5.6 years 5.6 years Baseball careers usually don’t last very long Baseball careers usually don’t last very long Baseball careers usually don’t last very long less than six years 5.6 seasons per a 2007 study that study