With the news that uber-closer Jonathan Papelbon has signed a record-breaking $6.25 million contract in his first year of arbitration, it’s clear that Papelbon has to be considered one of, if not the, best closer in the game now.

But how long will that last?

Papelbon has been increasingly reliant on his fastball over the last few years, ignoring his his slider (aka ‘slutter’) and for the most part, his splitfinger. Is this a good thing? Mmm… might be. Might not be.

Take for example an article I penned about a year and a half ago titled “Is Papelbon the best closer in the game?” This is in August 2007, and as you read the excerpt, you’ll realize how fast Papelbon has done a 180° to being strictly fastball-oriented.

It’s his constant adaptation to the game. Mariano Rivera crafted a
career out of his cut-fastball. Trevor Hoffman’s changeup is baffling.
Eric Gagne (when he uses it) has a tremendous curveball and changeup.
However, Gagne is struggling to adjust to life with a 93-mph heater as
opposed to 99-mph. Papelbon doesn’t have to adjust to life with a
93-mph heater; he lives at 93, but he can dial it up to 97 on command.
Even if an injury or old age saps his speed in the future, Papelbon
will be able to overcome it.

How? Consider that since he’s stepped foot into the major leagues,
he’s since developed a cut fastball and a splitter go to along with his
high heat. While he can snap off a curve or changeup on occasion, those
are largely forgotten pitches (for now). He’s constantly adjusting,
constantly striving to stay one step ahead of the scouting reports,
constantly trying to befuddle the hitters.

How times have changed. Let’s take a look at Papelbon’s pitch selection since his debut in 2005, courtesy Fangraphs:

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2005 75.6 9.6 0.2 1.2 13.4 1.0 1.5
2006 73.5 6.5 0.3 19.7 1.5
2007 78.1 6.2 15.7 0.4
2008 81.2 6.1 12.6 0.6
FB= Fastball, SL= Slider, CT=Cutter, CB=Curveball, CH=Changeup, SF=Split-finger, XX-Unknown, PO=Pitch-Out. Numbers are percentages of times pitch is thrown.

As you can see, he actually decreased his reliance on his fastball in 2006 — this is when he was shut down for September with arm troubles, mind you — but since then he’s scrapped any form of off-speed/breaking pitches and relied only on fastball and fast breaking pitches with minimal stress on the arm.

Since then, his fastball reliance has skyrocketed. He clearly possesses an excellent fastball, one that he can spot on command and has great late action.  He throws the fastball because it’s his bread and butter pitch and it’s the one that’s going to get a batter out.

Here’s the problem. What happens when Papelbon starts losing velocity on that fastball? His fastball averaged 95.3 miles per hour last year (92.9, 94.3, 94.3 the three years prior) but that’s not going to last. Velocity is the first to go as a player ages.  That’s not something we’re going to have to worry about for quite a few years, but it’s a logical question to bring up when you factor in his injury history.

Look, when Papelbot’s fastball starts waning, it’s obvious he’s going to have to start relying more on his other pitches. That means more sliders and split-fingers. Maybe even bring back the curve and changeup. These are all things that contributed to Papelbon’s injury.

Chris O’Leary feels that Papelbon is sensitive to future injury due to Papelbon’s hyperabduction:

Some people believe that is is critical that pitchers get their Pitching Arm Side (aka PAS) elbow up above the level of their shoulders at the high-cocked position because they believe that this will help to raise the pitcher’s arm slot. I believe that doing this, which I call Hyperabduction, leads to problems with the rotator cuff and/or the Labrum. What’s more, because a pitcher’s arm slot is a function of their shoulder tilt and not the height of their PAS elbow at the high-cocked position, following this advice with do absolutely nothing to alter a pitcher’s arm slot.

Increasing Papelbon’s reliance on off-speed pitches along with the hyperabduction theory means that Papelbon could have a far shorter career than anticipated — perhaps even follow the Dick Radatz career more than the Mariano Rivera career.

Speaking of Rivera, he’s lasted so long because he’s been very durable and relies on a cut-fastball that is so sickening that even if you know it’s coming and the location, you still can’t hit it. Even though he’s consistently been around 93 miles per hour for the last four years, when (not if) the velocity eventually decreases, he’ll still be able to hang around for a lot longer than most due to his movement. (Trevor Hoffman is a good example.)

Papelbon is around 94-95 now, but even dipping just two miles an hour to 92-93 (he averaged 92.9 mph in 2005) will cause hitters to catch up on his fastball more than normal. It can happen at any moment — just ask Francisco “K-Rod” Rodriguez, who spent last year averaging 91.9 on his fastball, two years after averaging 94.8.

So why did K-Rod succeed so much this past season when he broke the saves record? His off-speed pitches. His additional looks. Papelbon had that early in his career but doesn’t now and bringing these back may cause him be far more susceptible to injury.

Speculation of the future is pointless, of course. But the way the signs are pointing, Papelbon may indeed be a one-trick pony who will either suffer from decreased velocity (and effectiveness) or increased injury issues in the future.

Enjoy him while you can.