Let's take a look at the schedules of the Brewers and Mets.
Brewers have 9 games left. The Mets have 10.
This weekend at the Launching Pad, the Brewers need to take 2 of 3. The Mets will probably match with 2 out of 3 wins, but for this exercise...let's just say they go 1 for 3. The Brewers then have an off day Monday, while the Mets go play the Cubs. That Monday night, the Cubs will beat the Mets, and with 6 games to go each, we'll be tied.
The Mets play the Cubs 3 more times while we roll into Pittsburgh, whose players have been dying for the offseason the last 3 months so they can get some beach time in. We sweep Pittsburgh, while the North side losers better take 2 out of the next 3 with the Mets.
We have a 2 game lead in the WC (assuming Houston doesn't pull off 7 straight or something...I'm not even factoring that in) then going into the last series. Destiny is controlled. The Cubs are on cruise control...as they eye their postseason starting rotation they rest Z, Harden, & Dempster. We ship 2 out of 3, and get ready to play the Phillies.
Who else thinks this won't happen? It's basically a lock.