Over the last week, there was an interesting discussion on my post that examined how both the Phillies and Ryan Madson managed to become the losers of the off-season. It started when “Another John” wrote:
What if [Papelbon] is the next Rivera? How many years did it take Mo to become “Mo”?
A few others responded to that question and I was surprised to see how close Jonathan Papelbon and Mariano Rivera are statistically. Through his age 30 season, Papelbon has a 2.33 ERA, 10.7 K/9, 2.4 BB/9, and 4.4 K/BB. Through the same age, Rivera had a 2.63 ERA with a 7.9 K/9, 2.9 BB/9, and 2.7 K/BB. Of course, Rivera set himself from everybody else in the ten years since with his cut fastball, which most likely is not being properly accounted for with defense-independent metrics. For example, since 2002, Rivera has a 2.98 xFIP and 2.58 SIERA compared to Papelbon’s 3.09 xFIP and 2.51 SIERA. Papelbon has been excellent, but I think we can all agree that Rivera is better than those metrics indicate.
Commenter Dan K. put it best when he said:
Papelbon is effective largely because he can make hitters swing and miss with the best of them. However, if he doesn’t make them K, his batted ball profile is worrying. 44.1% FB, 36.6% GB, 19.4% LD. Are they terrible? By no means, but when you compare them to Mo’s (30.3% FB, 52.5% GB, 17.1% LD over the same time period) you see the difference in the pitchers. When Mo doesn’t get a K, you’re still not likely to be doing much damage. If Papelbon doesn’t get the K, there’s a much higher chance you’re doing damage.
One thing he failed to mention is that Papelbon has a track record of inducing weak fly balls. Per FanGraphs, his infield fly ball rate is 16.1 percent, best in baseball among all relievers. Rivera is not far behind at 15.7 percent. Both pitchers allow home runs at about the same rate as well, 6.6 percent for Papelbon and 6.2 percent for Rivera.
What worries me most about Papelbon is his pitch repertoire. Rivera became the greatest closer in baseball history with a cutter that no hitter has been able to figure out. Papelbon’s bread and butter is a high-velocity four-seam fastball (avg. 95 MPH, thrown 75 percent of the time), complemented by a slider (10 percent) and a sinking fastball (15 percent). As Papelbon ages (and perhaps is injured), will he be able to compete with a lesser four-seam fastball? Will those infield fly balls start heading into the outfield, perhaps over the fence?
The following heat maps, per ESPN Stats & Info, show Papelbon’s fastballs based on pitch location and release velocity:
We saw a similar story unfold with Brad Lidge. When Lidge came to Philadelphia after the 2007 season, he was one of the elite closers in the game with a nearly-unhittable slider. Following the magical 2008 season in which Lidge went 48-for-48 in save situations, he authored one of the worst seasons ever by a relief pitcher, finishing with a 7.21 ERA thanks to an inability to locate his slider, declining fastball velocity, and a general lack of good health. This was his age-32 season.
You can understand why the more statistically-inclined among us express apprehension when relief pitchers, especially those over the age of 30, are signed to long-term contracts worth lots of money. Rivera is one-of-a-kind; any GM thinking he signed the next Rivera must dodge some long odds and a plethora of hurdles through the years.
Papelbon certainly has the stuff to match Rivera’s numbers, but that is just one part of the equation. The rate at which his skill erodes and the frequency of his DL stints will have as much to do with his legacy as his strikeout and walk rates.