Aging and the Cubs

In my column today on BP I discuss the aging of teams and how that might relate, in the big picture anyway, to winning games on the field. In that column I showed an example of the Detroit Tigers from 1980 through 2006 and how team age tracked with winning percentage to a certain degree.

I thought it would also be interesting to take a look at the Cubs and so the graph below tracks the Normalized Weighted Age or NWA (defined as the weighted age of the team divided by the mean weighted age for the league and year where weighted age is calculated by weighting plate appearances and innings pitched and then multiplying the position player age by .6 and the pitcher age by .4) and winning percentage by year.



What's interesting here of course is that as the Cubs teams of the late 1960s with Ron Santo, Billy Williams, and Fergie Jenkins matured they improved. In the 1970s the team age fell to around league average and the record hovered just under .500. As the 1980s dawned the team initially got younger before Dallas Green brought in a set of veterans (Larry Bowa, Ron Cey, Gary Matthews, Dennis Eckersley) that took them to a .596 winning percentage in 1984.

Those veterans then moved on or retired and a very young team (Mark Grace, Jerome Walton, Dwight Smith, Greg Maddux) in 1989 was able to become an exception to the general rule and win the division. The team then got older in the early 1990s (Grace and Ryne Sandburg being the core) and returned to mediocrity before bringing in veteran pitchers like Kevin Tapani and Terry Mullholland and position players Gary Gaetti, Mickey Morandini, Scott Servias, and Lance Johnson along with a maturing Sammy Sosa for their Wild Card berth in 1998.

That team as well was on its last gasps and quickly crashed although they restocked with veterans Eric Young, Matt Stairs, and Jon Lieber to remain respectable in 2001. The young pitchers combined with a good mix of veteran and young positions players had the Cubs in the "sweet spot" in 2003 and 2004 although they did not capitalize. The last several years are more painful but obviously the team has gotten younger (especially on the mound in 2006) and performed poorly.

Given the massive free agent spending this winter the NWA for 2007 will likely rise to the 1.2-1.5 range and Cubs fans anyway, expect the winning percentage to rise as well.