Behind every MLB contender, there's a dirty little secret.
Keep winning, and nobody pays any attention to it. The Red Sox, for instance, have been on such a tear lately that nobody's asking why David Ortiz (.237 average, .287 on-base percentage, .342 slugging) looks so washed-up.
The Dodgers have hummed along so nicely that no one's sounded the alarm on how the back end of the starting rotation is a disaster in progress (Clayton Kershaw's last two starts: Nine innings, 18 hits, six walks, 15 earned runs).
Stumble, however, and those unpleasant truths start to surface.
If you stagger out of the gate 9-9 while your arch-rival races to a division lead—the Cubs' M.O. thus far—people are going to pry.
Chicago's dirty little secret?
The window for this aging core to win is closing fast.
Because the Cubs' current cast labored through multiple seasons of non-playoff obscurity before taking two straight NL Central titles, it doesn't have the same long-in-the-tooth feel as a perennial winner like the White Sox or Yankees.
But while this group may be green when it comes to success, plenty of its key contributors are going gray.
Derek Lee turns 34 in September. Aramis Ramirez hits 31 in June. Ted Lilly is 33 and Ryan Dempster will join him Sunday. And while Alfonso Soriano (33), Kosuke Fukudome (32), and Milton Bradley (31) are all new additions, their legs are plenty old.
Chicago's recent ascent hasn't been a product of developing young talent, but rather importing veteran help. The trouble is, those veterans are starting to show the wear and tear of a few too many campaigns.
Lee left Sunday's game after the first inning as the neck spasms that have plagued him since 2007 flared up. He's listed as day-to-day.
Ramirez hasn't played since Friday with a calf strain. He's missed 30 or more games in two of his past four seasons.
Bradley has been limited almost exclusively to pinch-hitting duty after an April 12th groin injury. He, of course, has managed just one full season as a position player in his 10-year career.
In the short run, the injury parade has meant a healthy dose of Reed Johnson, a coming-out party for Micah Hoffpauir, and a .500 start.
In the long run? We're looking at the beginning of the end.
And things could even get worse.
Soriano has spent time on the disabled list in each of the past two seasons. His hamstrings aren't getting any younger and, given his new-found realization that he's allowed not to swing once in a while, his absence would deal a big blow.
Lilly had never topped 200 innings pitched before coming to Chicago. Before Dempster returned to the rotation last year, his last full stint as a starter ended in Tommy John surgery. Lose one of those two this year, and Cubs fans are going to start pining for the good old days of Jason Marquis.
But the injuries are only half the problem. Even a healthy Lee started the year hitting .209 with a .313 slugging percentage. A healthy Dempster has posted a 4.88 ERA and 1.42 WHIP that track much more closely with his career numbers than his stellar '08 did.
Bradley managed just one hit in 22 tries as a starter before submitting a singularly useless 0-for-8, five-strikeout performance off the bench.
This is a roster for which the notion of "upside" is a distant memory. This is a team with nowhere to go but down.
Unless new owner Tom Ricketts likes to eat payroll, that's not changing any time soon. The Cubs' 30-and-older regulars are owed an average of $12.45 million a year through the 2010 season.
Forget about waiting 'til next year for once. If this roster has a championship run in it, it's likely now or never.
Want to hear a dirty little secret, though?
It may already be a year too late.