I agree on this. There isn't a rivalry until they, and another team from the central, are good for years. Not sure if they will ever have a clear "life-long" rival, like the Yanks and Red Sox, or Giants and Dodgers, or Cubs and Cardinals, but if I had to pick I would say Detroit. I may be biased because I live in Michigan, but even just proximity purposes, Detroit and Chicago probably butt heads more than any other duo in the central. Sox and Royals might be a close 2nd. Maybe if Milwaukee were in the division it might be a different story.
With that being said, is there really any other division rivalries in the central?