One quote from Phillips caught my eye:
I definitely think [the closer mentality] exists. You have to have a short memory—about everything. If you’re throwing great, remember how it feels and go back out there to do it next time—and if you throw badly, you got to let it go. The thing is, if you throw badly, your team normally loses if you’re a closer. I mean, very rarely can you make a mistake and still win the game. I would define it as... I’m not sure if it’s being cocky or just extremely confident, because you definitely need to have a little bit of a swagger about you—just because you’re out there when it matters the most, and [laughing], if you throw bad you lose. So it’s just rebounding and forgetting any bad things that happen.A common problem that even very smart general managers make is to waste money on average relievers because they have closed in the past. For example, Joe Borowski would be making much less money than he is now if he had produced identically in middle relief during his career. Having said that, Phillips does make an interesting point in that the negative reinforcement that comes with being a closer is very severe.
It's difficult to measure what impact mentality has on a closer's performance and the typical responses are shrouded in cliché. With the stakes being the highest any pitcher can face it does put more pressure on the pitcher, and teams need someone that can handle pressure and adversity well. But pitchers that don't handle adversity or pressure well are probably going to get weeded out before they're able to reach the major leagues or won't be likely to rise to the role of even setup man.
Teams undergo self-inflicted pain all the time when they sign washed up former stoppers like Jose Mesa and Armando Benitez on the qualification that these pitchers have experience dealing with the pressures of the ninth inning while failing to take notice that there are other relievers who actually are more effective pitchers. There's also a closed feedback loop in play when only pitchers who have experience closing are looked to in filling the closer role—how is anyone else going to gain that experience?
One thing the Twins have done well in the past is to buck the trend of overpaying for experience and instead promoted successful setup men to the closer role. Neither Eddie Guardado or Joe Nathan had closed before the Twins anointed each pitcher their closer and the Twins have averaged 41.8 saves a season out of their stopper since 2002.
With the Twins facing some tough financial decisions in the coming years about which veterans to sign to longterm contracts (Santana, Mauer, Morneau, Hunter, Cuddyer, and Nathan), they shouldn't make the mistake of paying a premium for Joe Nathan. As amazing as he has been, his title is going to inflate his salary. Nathan has been the best reliever in baseball over the span of the past three seasons, but I don't buy that there is a $9,000,000 difference between him and Pat Neshek. The Twins won't be able to resign everyone and need to make efficient payroll decisions. Paying more for performance and less for labels would be a good start.