There's a pretty solid chance the division still has everyone over .500 on June 1st. Pirates and Reds only need 6 more wins the rest of the month. Pirates schedule looks very manageable, Reds is a little tougher, but only because they play Atlanta at the end of the month, so I can see them getting swept and that pushing them under. Cubs, Cards, and Brewers would need a big losing streak to fall below .500 by then. It's also possible that with everyone having built up a big interleague record already that unless one of the Central teams starts dominating everyone else in the head to head playing each other more doesn't push the division under .500 just towards it. You figure at some point 1 of the teams will likely hit a rough patch, but at some point the reality may well be that everyone in the Central has at least a respectable team this year.