No active managers come within five years' service of Cox' twenty-eight years. Mike Scioscia has the same .556 winning percentage as Cox, and a couple of names beat Tony LaRussa's .535 winning percentage. Lou Piniella has seven playoff appearances, to top the list of those not members of the triumvirate. LaRussa has got the fewest of the three, with thirteen of his seasons ending at some point in the postseason.
Here's a chart, showing all active managers with at least nine years of service and five postseason appearances, in each case roughly one-third of Bobby Cox' totals.
Manager Years Win Pct. Postseasons
Lou Piniella 22 .521 7
Mike Scioscia 10 .556 6
Terry Francona 10 .525 5
Jim Leyland 18 .496 5
Outside of these four, Ron Gardenhire will make the list if he starts next season in a manager's job. Charlie Manuel, Dusty Baker, Cito Gaston, and Bruce Bochy all need to make the postseason as well as keeping a managing job through to next season. But, as with Leyland, the postseason section of the curricula vitarum of the last three will look a bit weak.
Lou Piniella will certainly lay claim to Cox' triumvir status if Cox retires after this season, but whether he'll hold it for long is an interesting discussion point. I don't think he has enough postseasons to make a solid claim, which makes the long-term bets one of Scioscia and Francona. Who do you think is the best claimant? Answers on a postcard, or in the comments box.