So who is the real ace of the Cubs' pitching staff?
When the season started, the undisputed ace was righty Carlos Zambrano. Now, it just might be righty Ryan Dempster. And Dempster's strong season raises interesting questions about who will start a postseason opener, if the Cubs make it that far.
Dempster is the Cubs' winningest pitcher with a record of 14-5, and his ERA of 2.92 is the best among Cubs starters. Zambrano is 12-5 with a 3.38 ERA.
Several of Dempster's peripheral stats also top Zambrano's. His WHIP (walks plus hits per one inning pitched) is 1.16, compared with Zambrano's 1.25. Dempster has 149 strikeouts, compared with 107 strikeouts for Zambrano. Opposing batters have a .292 on-base percentage versus Dempster, compared with .310 off Zambrano.
In recent starts, Zambrano has been inconsistent with his delivery and command. He still has a tendency to let his emotions get the best of him when things aren't going right on the mound.
The final six weeks of the season will determine a lot as far as any playoff rotation goes.
