Here's what I would do:
NL East: Mets, Phillies, Braves, Expos/Nats
NL Central: Brewers, Astros, Cardinals, Cubs
NL West: Giants, Padres, Dodgers, Rockies
AL East: Red Sox, Yankees, Orioles, Rays
AL Central: Twins, Royals, Tigers, Indians
AL West: Mariners, Rangers, A's, Marlins
Thinking: The Marlins are the odd team out. Ship them out to the AL West to allow every other team to be in its rightful division. It's been done several times before, most recently moving them to the AL East a few legs back. Did they make the playoffs that season?