It's simple...
Cubs vs. Cardinals
Starting pitching: Advantage Cardinals
Relief pitching: Advantage Cubs
Hitting: Advantage Cardinals
Fielding: wash
Winner: Cardinals
Cubs vs. Reds
Starting pitching: wash
Relief pitching: Advantage Reds
Hitting: Advantage Reds
Fielding: Advantage Reds
Winner: Reds
Cubs vs. Brewers
Starting Pitching: wash
Relief Pitching: Advantage Cubs
Hitting: Advantage Brewers
Fielding: wash
Winner: tie
So by trading away the farm for Matt Garza, the Cubs have moved themselves into a tie with the Brewers for third place in the NL central.
Now the Cubs have much less to work with to try to trade for a second baseman, a replacement for Carlos Pena and a replacement for Aramis Ramirez after the 2011 season...
All so they can compete for third place in the NL Central.
Nice.