The Value of Joe Nathan

One of the enjoyable aspects of the internet and how it's affected the way we cover sports is the advent of statistical analysis.

This isn't about just the things -- OPS, primarily -- that somehow got labeled as Moneyball creations. However, that part of the business of baseball has changed the way many people view the game.

While "value" is still a tough thing for many baseball people to grasp, there are metrics on the topic. Baseball Prospectus has for some time published a stat called "Value Over Replacement-level Player," or VORP. VORP is designed to produce a calculation of how many runs a player produced (or prevented) over a cheap, bargain-basement type player employed at that same position.

I caught some heat with friends for arguing that the Joe Nathan injury wasn't all that disastrous for the Twins. My feeling is that Joe Mauer is a much more important player on this team, and truly someone they can't afford to lose, while Nathan -- while really good -- fills a role that is much more replaceable. The bottom line wasn't any disrespect toward Nathan. I think the world of the guy as a closer, but he's a ninth-inning guy.

Exactly how much of an impact can he have on the Twins' success?

Joe Posnanski has some numbers.

Here are Joe Nathan’s statistics against the other four teams in the American League Central:

Kansas City Royals: 3-0, 0.85 ERA, 35 saves, team hitting .144 against him.
Detroit Tigers: 2-1, 1.55 ERA, 30 saves, team hitting .153 against him.
Chicago White Sox: 3-2, 2.06 ERA, 24 saves, team hitting .151 against him.
Cleveland Indians: 3-1, 2.98 ERA, 26 saves, team hitting .201 against him.

Oy.

Granted, the AL Central stinks, but those are some serious numbers. Nathan must be a huge value to his team, right?

Well, then there's this, also pointed out by Posnanski.

In 2008, the Phillies were second in the league in runs scored, and fourth in ERA, and closer Brad Lidge was virtually unhittable – he saved 41 games in 41 opportunities. He finished fourth in the MVP balloting.

In 2009, the Phillies were first in the league in runs scored, sixth in ERA, and closer Brad Lidge was a fiasco – he was 0-8, with a catastrophic 7.21 ERA and 11 blown saves. The Phillies won one more game in 2009 than they did in 2008.

So what's the answer?

My earlier argument for Francisco Liriano going into the bullpen was as much built on Liriano's arm troubles as it was Liriano's inherent value as a starting pitcher. However, as Patrick Reusse notes, the Twins are in potential trouble if Liriano can't start.

The difference between a closer like Joe Nathan and an average closer is 4.5 percent -- Nathan's 91 percent and an average of 86.5 for all pitchers trying to close a victory in the ninth inning.

The difference between the Liriano described by Gardenhire on Sunday and the gutsy (Brian) Duensing is a percentage that's incalculable.

This is an interesting point, if you assume it's either Liriano or Duensing for the fifth starter spot behind Scott Baker, Nick Blackburn, Glen Perkins, and Carl Pavano. You also have to assume that the Twins can plug in anyone to Nathan's role and get a league-average performance.

But where are the Twins more likely to get that league-average performance? Out of a guy who pitches just one inning, or a guy who has to throw five or six consistently to be effective? If Duensing struggles, Liriano is the next-best candidate to start in that fifth spot. A healthy and effective Liriano -- hard to argue the point that he's looked good so far in the spring, for what that's worth -- is much better than Duensing, and he's much more helpful to this team starting than he is closing.

Liriano as a closer should be a last resort to salvage his career. Upon further reflection, it doesn't appear we're at that point yet.

Meanwhile, Nathan's VORP last season was 26.2. That ranked him third in baseball among relief pitchers. Baseball Prospectus -- in their 2010 annual -- projected a dropoff to a VORP of 16.1 this season. That would put him in the neighborhood with guys like Jose Valverde or Huston Street, who aren't bad relief pitchers but also aren't Joe Nathan.

Can the Twins just automatically count on whoever closes -- Matt Guerrier, Jose Mijares, Jon Rauch, or whatever they think of -- duplicating even a 16.1 VORP?

On the flip side, of the star players the Twins could lose, isn't this the best-case scenario? The Twins have a good starting rotation, plenty of options in the bullpen, including a lefty (Mijares) and a side-winder (Pat Neshek).

Nathan will be missed, but it could be argued that he was about to slip a bit in his production (BP's projections saw the slides from Dice-K and Josh Hamilton coming last year, so while their projections aren't gospel, they do good work.)

The Twins lived without Morneau last year for the final month, but it doesn't seem like a good long-term plan to have him on the shelf for that length of time again.

Meanwhile, Mauer's VORP last year, while often carrying the offense, was 77.5. His backup is Jose Morales, whose VORP was 3.7.

So, tell me again, who would you rather replace?