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Thursday, May 23, 2013
Closer look: Defensive starter projections

By Mike Sando

We interrupt ongoing coverage of Michael Crabtree's surgically repaired Achilles tendon to continue our recent discussion on average ages for projected 2013 NFL starting lineups.

Offense went first. Defense is up next.

The chart ranks teams by average ages for defensive starters.

I've recalculated the numbers and you can see just how close some of them are -- indistinguishable, in some cases. One change to the projected starting lineup could affect the order by several places.

The way the ages are calculated -- number of days since birth divided by 365.25 to account for leap years, then rounded down to the tenth of a year and averaged -- can cause slight changes to the order from one day to the next. That happened with the defenses for New England and Baltimore over the past couple days, for example. They actually switched places from a couple days back because the calculation for Tommy Kelly's age changed from 32.3 to 32.4.

For that reason, I'm more interested in the extremes from one end of the rankings to the next. A few spots here or there? No big deal.

The gradual changes add up through the range of teams, and we can see why the Chicago Bears weren't all that excited about bringing back Brian Urlacher to a defense that has the oldest starting linebackers without him.

A few thoughts on the defensive numbers for NFC West teams: