What’s Joe Nathan Worth?

The St. Paul Pioneer Press writes that Joe Nathan wants to finish his career as a Twin and would like to discuss an extension this summer.  The Twins have him signed for 2007-08 at a well below-market $11.25MM.

Since no top tier closers were on the free agent market this winter, we didn’t directly see the inflation for them.  However, consider the AAVs for these relievers, who are closer candidates or closed recently:

Danys Baez – $6.33MM
Eric Gagne – $6MM + $5MM in incentives
Octavio Dotel – $5MM + $2.25MM in incentives
Keith Foulke – $5MM + 2MM in incentives
Justin Speier – $4.5MM
Joe Borowski – $4.25MM + $1.5MM in incentives

This is a motley crew.  Baez posted a K rate below 6 per nine and got three years.  Gagne has pitched 15 innings over the past two seasons.  Dotel, 25 innings. Foulke is shaky to say the least. Speier is reliable but it took four years.  Borowski is pitching with a messed up shoulder.

Now consider Nathan.  He’ll probably sign for a discount, but imagine if he went to the highest bidder.  He’s had four straight years of relief dominance, no matter how you measure it (saves, VORP, ERA, whatever).  He’s pitched his last three seasons in the AL.  He hasn’t allowed a baserunner per inning since ’03.  And he’s somehow getting better each year.

The biggest guaranteed deal for a closer was Billy Wagner’s four-year, $43MM contract last year.  Wagner was 35 in the first year of the deal, while Nathan will be 32 next season.  If Nathan were to hit the open market after 2007, could he get a five-year, $65MM deal?  Even more from the Yankees?