New York Yankees Brett Gardner is chased by Boston Red Sox Victor Martinez at Yankee Stadium in New York

Victor Martinez has publicly stated he would like to extend his contract with the Boston Red Sox and perhaps even finish his career here.  I don’t doubt he would like to stay here, but the question we have to ask is how much will it cost to get it done.  He would like to have something before the season starts.

The first question is the length of a new deal.  This will be his age 31 season and he would surely be looking for a four to five year deal.  With his ability to get on base and solid power I don’t see a problem with that length of deal, but we should immediately think how long can he last behind the plate.

His defense is not as bad as many think, but he still has a poor arm for catching runners.  It’s really hard to value the skills defensively as a catcher, but eventually it’s known Martinez will have to move to either first base or DH.  With Kevin Youkilis signed through 2012 and an option for 2013 first base isn’t an option unless Youk moves back to third.  Making that move will be tougher to do each year he is getting older.

That leaves DH for Martinez, but how likely is it that Martinez would be set as a full time DH?  Possible, but once David Ortiz finishes his time in Boston it’s likely the Sox go with a rotation at DH as many other teams are employing the past few years.  This means the Red Sox have to trust that Martinez will be able to play a large amount of his games at catcher for the length of the deal.

The good news for Martinez is with position adjustment his baseball bat is worth much more behind the plate.  He has been around a 5 WAR player since 2004 ignoring his fluky 2008.  That type of player is worth around $20 million per season , but that has started to change.  The current market is only paying about $3.5 million per WAR, so his value is closer to $17.5 million on these numbers.

That’s quite a steal for the Red Sox right now as Martinez is due $7.7 million for the 2010 season right now.  I’m sure Martinez would like to see that number go up as part of any extension as well.

He will be 31 this year so aging is becoming a factor and the projected age decline is 0.5 WAR lost per year.  That means he will have values of 5.0 in 2010 and then 4.5, 4.0, 3.5 and 3.0 in the years 2011 to 2014 seasons.  That is all based on a majority of time at catcher and totals 17 wins above average in the next four years and 20 in the next five years.

This gives Martinez a rough estimate of $60 million dollars value four the next four years based on the new free market values of $3.5 million per win.  The five year deal has a value of $70 million.  These again are based on the new market and fair based on his position of being under control for 2010 and not being a free agent yet.

My opinion is his defense is acceptable to proceed with Martinez behind the plate for the next 4 years.  You could up his 2010 value and give him a fresh deal for 4/$60 or look to give him 3/$42 that starts after the 2010 season.  Either way those deals are fair market for where the current deals are going.

If Martinez thinks the market is going to be back after 2010 he could think he is due the $4.5 per win above average.  That makes him worth $90 million for the next five years.  I can’t see the Red Sox going to that amount with a player under team control.  They are known for being willing to go to free agency and even let players walk.