Jake Arrieta is Jason Hammel — Kind Of

This past week, Dan Connolly was talking to Jason Hammel about the struggles Jake Arrieta has been going through this season.  Here is an excerpt:

“I know exactly how he feels,” said Hammel, who was the Orioles’ Opening Day starter this year at age 30. “Honestly, he reminds me a lot of myself. It was three or four years of impressive stuff and inconsistent results. And it was frustrating.”

Hammel did not mean it in the way I will now take this article, but I found that to be an interesting statement because Hammel’s stuff is quite similar to what Arrieta has.  Two weeks ago, Stephen Loftus wrote an article on pitching similarity scores for Beyond the Box Score.  Loftus took data recorded by Pitchf/x and used a few formulas to compare pitchers for these attributes: handedness (pitcher and batter), velocity, horizontal/vertical movement, locations, and release point.
When you put all of these together, you get these top comparisons for the Orioles original starting rotation (Loftus considers anything above 0.80 as being “Extremely Similar”):

Jason Hammel
Jake Arrieta (0.91), Jeremy Guthrie (0.90), Jordan Zimmerman (0.88), Justin Verlander (0.86), and Tyler Chatwood (0.85).
Jake Arrieta
Jordan Zimmerman (0.91), Jason Hammel (0.91), Ivan Nova (0.87), Josh Johnson (0.87), and Jeremy Guthrie (0.86).
Wei-Yin Chen
Wade Miley (0.83), AJ Griffin (0.81), Tom Gorzelanny (0.79), Felix Dubront (0.79), and Madison Bumgarner (0.79).
Chris Tillman
Grant Balfour (0.84), Wade Davis (0.79), Clayton Kershaw (0.77), Mat Latos (0.75), Brandon Beachy (0.74).
Miguel Gonzalez
Brian Matusz (0.80), Tim Lincecum (0.79), Ubaldo Jimenez (0.78), Bud Norris (0.77), and James McDonald (0.77).

Looking at this comparisons, it is difficult to immediately recognize the utility of this exercise.  We do not know exactly how well stuff relates to absolute performance.  Tentatively, we can look at these numbers and come away with a few things:

• Jason Hammel and Jake Arrieta appear to be a similar style of pitchers and find themselves in a grouping of incredibly successful pitchers (e.g., Justin Verlander, Jordan Zimmerman, Ivan Nova).  Of course, there are some rather mediocre pitchers in that groups as well.
• The other three pitchers have rather unique repertoires as starting pitchers go, which may simply mean that they are unique or that their tool box is ill-suited for starting.
• Wei-Yin Chen’s comparison to Wade Miley and AJ Griffin is hopeful.  Both have been solid pitchers who are able to do more than the quality of their pitches would suggest.
• Chris Tillman’s top comp being a relief pitcher foretells his future if he is unable to figure out his control.  Tillman simply needs to be more efficient with respect to his pitch counts in order to get himself deeper into games.  Now, becoming efficient is not so simple.
• Miguel Gonzalez’ success seems remarkable after we have seen so much of his top comp, Brian Matusz, in the rotation.

With those points in mind, we have to remain sober as to what we can really expect these comps to mean.