Joe Nathan By The Numbers

The Minnesota Twins officially announced yesterday that they had declined Joe Nathan's $12.5 million option for 2012, choosing instead to pay his $2 million buyout and bid for his services on the free agent market.

This was bittersweet news for Twins fans. Intellectually, most Twins fans agree that picking up Nathan's option - which would have covered his age-37 season - would have been a mistake, especially given the number of holes on the team that need to be filled this offseason. But Nathan ranks as one of the most popular players in recent Twins history. On an emotional level, the prospect of seeing Nathan end his career in a different uniform is a painful possibility for many Twins fans.

If this is the end of Nathan's tenure with the Twins, I thought it'd be a good time to step back and put Joe's career in some perspective.We'll dive in after the jump:

We all remember back in August when Nathan set the franchise saves record when he recorded his 255^th save as a Twin. Here's a list at the names Nathan bypassed in his seven seasons pitching for the Twins:

Nathan pitched 463.1 innings for the Twins while accumulating those 260 saves, posting an ERA of 2.16 and an absurd 4.19 strikeout-to-walk ratio. His 2.16 ERA is the lowest among any Twins pitcher in history (1961-2011) with at least 400 innings pitched:

He also ranks as one of the franchise's all-time great strikeout artists. Among all Twins pitchers who have thrown more than 100 innings, Nathan's 10.9 K/9 ratio ranks at the top of the list:

I think it's pretty clear from the charts above that Nathan easily ranks among the Twins all-time great relievers, if not the best in team history. But how important was Nathan to the Twins recent run of division championships and playoff appearances?

Nathan became the team's closer in 2004, joining the club after they had just won back-to-back division titles in 2002 and 2003. With Nathan closing the door, the team would go on to win three more division titles in the next six seasons, narrowly missing a fourth title in 2008. Typically when we want to figure out a player's value from season-to-season we turn to Wins Above Replacement. However, WAR is awfully hard on relievers, a fact that has been the subject of many debates and discussions since the metric began receiving considerable acceptance (for more on the subject, start here). So while WAR won't credit Nathan with a major share of the team's success over the past 8 years, there is one well-regarded metric that thinks Nathan has been the team's MVP since he joined the club in 2004.

Judging by Win Probability Added (WPA) - which you can read about here if you're not already familiar with the concept - Joe Nathan has been the single most valuable Twin during his time with the club. And it's really not very close:

Finally, let's look at how Joe has matched up with the best relievers in the game during his eight years with the organization. Even though Nathan missed all of 2010 and was out of the closers role for a substantial portion of 2011, his 260 saves with the Twins ranks as the fourth best mark in all of baseball since 2004.

Among all pitchers with at least 400 innings pitched since 2004, Nathan's 2.16 ERA with the Twins is the second-lowest mark in baseball:

If you look just at 2004 through 2009 (the timeframe before Nathan underwent Tommy John surgery), Joe had the lowest ERA in baseball (1.87).

Last but not least, any discussion about Nathan's tenure with the Twins would be incomplete without at least mentioning the franchise-altering trade that brought Nathan to Minnesota. Everyone here knows the details, and there's not much I can add that hasn't already been written. Below is an updated accounting of the trade, using the WAR received by each team from the players they acquired in the deal.

The Giants non-tendered Pierzynski after his one season with the club in 2004. Nathan and Liriano were still pitching for the Twins - with varying degrees of success - in 2011.

It's been an absolute pleasure to watch Joe Nathan pitch for the Minnesota Twins over the past eight years, and I wish him well in free agency and in sustaining his career in 2012 and beyond (whether it's with the Twins or some other team not named the Yankees, White Sox, or Tigers).