Sunday morning’s edition of the Star-Tribune announced that the Twins were interested in locking up their most valuable player to a long-term contract. Was that Justin Morneau, the AL MVP? Joe Mauer, their most valuable commodity in terms of marketing? Maybe their most valuable post-season asset: two-time AL Cy Young winner Johan Santana? Well, kinda, but it was the other guy in the story that caught my attention – Joe Nathan.

Is it a revelation? Is it even news? Because other than the headline (“Santana, Nathan moving to top of Twins' to-do list”) just about everyone involved seems to be pretty careful about whether or not this is a priority. Let’s count the caveats, shall we?

Twins officials confirmed Saturday that, after the club signs its six arbitration-eligible players(1), it will approach Santana and Nathan about contract extensions to ensure they are in Twins uniforms when the new park opens.

"We have a lot of things going as far as the arbitration-eligibles(2), as most clubs do," Twins General Manager Terry Ryan said. "You kind of let the calendar dictate our procedure(3). I'd like to take care of first things first(4), then see where things take us(5).

"If you want to do something(6), you approach the people you are responsible to and see if there's anything to be talked about(7)."

Ryan acknowledged that he had preliminary(8) talks with agents for both players during the winter meetings.

Wow. Eight attempts to dampen the impact of the story inside of 125 words. That’s some solid backpeda…er…clarifying by La Velle E Neal. OK, that was a cheap shot, and not a deserved one, because Neal doesn’t make up the headlines. What’s more, it seems like he’s really trying to not overinflate the news that the Twins have explored locking up some key players for when the new ballpark opens.

The question is whether Nathan counts as one of those key players. The value of a closer has been a popular debate recently, and it doesn’t fall cleanly along the sabremetrician/traditionalist border. There are plenty of sabremetricians that wonder if we don’t underestimate the value a dominant game-ending pitcher can have. There are also plenty of traditionalists who wonder if the obscene salaries being paid to these guys are justifiable.

And make no mistake, the salary that Joe Nathan could demand is obscene. No premier closers signed during this latest offseason, so keep in mind that the numbers I’m about to throw out were negotiated when there was still some sanity in the free agent market.

• BJ Ryan was 30 and had only saved 42 games in his career, but signed a five-year, $47 million contract with the Blue Jays last offseason.
• Billy Wagner was already a premier closer, and at 34 years old he signed a four-year, $42 million deal with the Mets shortly after Ryan signed.
• Trevor Hoffman was 37 years old, and signed a two-year deal with the Padres for $13.5 million to stay with his team.

When Nathan’s contract with the Twins ends in 2008, he’ll be 33 years old, and will have been more durable than Wagner. A $50 million contract isn’t out of the question. Which means the Twins would need to commit roughly 1/8 the of their payroll to their closer, and they would continue to do so through the season that he turns 37 years old.

It’s tempting to close the door right there. Given their payroll constraints, the immediate reaction for many can be summed up as IOFI – It’s One Frickin’ Inning. Even memories of LaTroy Hawkins won’t persuade some that just about any above average reliever can get through an inning fairly successfully, and the fact that it happens to be the ninth doesn’t change much. I suspect it can be demonstrated statistically.

But I KNOW that an incredibly consistent closer can be shown to be valuable statistically, because Nathan did it last year. Turns out there’s a slick little tool for measuring how valuable a player was in a specific year. It doesn’t just tell you how well the player performed, but how well they performed at the times that meant the most.

It’s called Win Probability Added, and it basically measures how much a player helped his team win or lose every game. So, pitching a scoreless sixth inning when his team is down by four runs isn’t nearly as valuable as pitching a scoreless ninth inning when his team is tied, and the game is in doubt.

(For now, we’ll stop there with the explanation. If you want to wade just a bit deeper, there’ll be more in a footnote below this entry. Check it out - I bet you’ll like it. It’s logical and requires nothing more complicated than subtraction. It’s really kinda fun. And yes, I’m talking to you, Mister/Miss Artsy-fartsy.)

Anyway, you can find the Twins players’ 2006 WPA here. It confirms a lot of things that you probably suspected - Morneau’s clutch hits were huge for the team, Santana’s starts carried the pitching staff, and while Mauer hit awfully well, he didn’t impact games like Morneau did. But all three of them were secondary to Nathan, whose clutch performance landed him at the top of the list.

Which doesn’t solve the debate, but it might frame it differently. Nathan has been worth every penny so far, and would be even with a big pay hike. And while the Twins have plenty of other candidates for the closer’s role, don’t kid yourself into thinking that we can rely on his replacement to have the same kind of consistency. Or that a change won’t cost the team any wins.

Here’s how WPA works, pulled straight from Wikipedia:

“The Win Probability for a specific situation in baseball (i.e., men on second and third, two out) is obtained by first finding all the teams that have encountered this situation. Then the winning percentage of these teams in these situations is found..…Win Probability Added, thus, is the difference between the Win Probability when the player came to bat and the Win Probability when the play ended.”

For example, let's say that it’s the bottom of the eighth, the home team has a four run lead with two outs and a runner on second base. Of course, this isn’t the only time that this has happened. In fact, it’s happened 784 times since 1979, and the home team has won 777 of them. So empirically, the home team has a 99.1% chance to win the game.

But hold on. The next batter on the visiting team hits a home run, and cuts the lead to two runs. Leading by two runs in the eighth inning with nobody on base, the home team has won slightly less: 95.2%, or a Win Probability of .952. So that home run swing improved the visiting team’s chance of winning the game by 3.9%, and the batter is awarded a WPA of .039. The pitcher that gave up the home run would likewise be deducted .039 from his WPA.

For more stuff on WPA:

• Fan Graphs has the list of Win Probability Added tallies for each player and team from 2006(http://www.fangraphs.com/index.aspx).
• Will Young’s Twins Page talks a lot about WPA as the season goes on, often giving each game’s results (http://www.wyoung.net/twins/).
• Christopher Shea compiled the Retrosheet data into an easy to use template on his website (http://www.walkoffbalk.com).
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Twins Geek is the editor and part-owner of GameDay, the independent baseball program sold by vendors across the street of the Metrodome. He's occasionally filling in for Bat Girl this offseason while she gets some R&R.