How Luke Gregerson does it

Before the 2009 season, the San Diego Padres traded their starting shortstop, Khalil Greene, to the St. Louis Cardinals for reliever Mark Worrell and a player to be named later. At the time, the trade was met with mixed emotions in Padre-land, as Greene was coming off the worst season of his career, one that saw him collect a .264 weighted-OBA and near replacement level performance overall. He was still, however, the mainstay at shortstop for the Padres and a fan favorite.

Looking back now, it is not difficult to see that the Padres made out well on this deal. Greene’s career continued to spiral in St. Louis and the PTBNL turned into Luke Gregerson, a guy who has quickly developed into one of the best late-inning relievers in baseball.

Busting out a copy of the 2009 Baseball America Prospect Handbook finds Gregerson ranked 29th in the Cardinals’ system at that time. After being selected in the 28th round of the 2006 draft, Gregerson quickly rose through the Cards’ system in the reliever role, striking out more than one batter per inning at every level, showing solid enough control, and not surrendering a home run until he reached Double-A ball in Springfield. While Gregerson excelled on the mound, he certainly did not earn “can’t-miss” prospect status, evidenced by the relatively low ranking by Baseball America.

Sure, the numbers were great, but he did not really posses the overpowering stuff that you would like out of a relief pitching prospect—at least in terms of miles per hour.

Fast forward to right now, where Gregerson is in the midst of a tremendous sophomore season with the Padres, sporting a 2.46 ERA, but even better underlying numbers—11.4 strike outs per nine, 1.3 walked per nine, and .7 home runs per nine. A look at Gregerson’s career so far better displays his brilliance:

Year    Innings ERA     K/9     BB/9    HR/9    FIP     xFIP    WAR
2009      75    3.24    11.2     3.7     0.4     2.5    3.11     1.8
2010    40.1    2.45    11.4     1.3     0.7    2.09    2.31     1.2

Gregerson has not amassed many major league innings, as a reliever just halfway through his second season, but so far the returns have been top-notch. After a great rookie season in which Gregerson put up a three strikeout-to-walk ratio, he has improved so far in 2010. His strikeout rate has remained exceptional and he has dramatically reduced his walks, though he is allowing home runs at a slightly higher clip.

Gregerson’s Fielding Independent Pitching (FIP), which measures a pitcher’s performance through strikeouts, walks and homers allowed, has been very good in his first two seasons, sitting at 3.11 last year and dropping further to 2.31 this season. FanGraphs has his Wins Above Replacement (FIP-based) at 1.8 last year and 1.2 this year. Those numbers are particularly strong for a reliever who does not find himself in the closer role, and oftentimes in a stacked bullpen featuring the likes of Mike Adams and Heath Bell, so does not pitch the team’s most critical innings.

If you trust those WAR figures, Gregerson’s performance has been worth almost $13 million so far in his short career, on the free market. In that time, he has been paid somewhere in the range of $600,000, giving him a surplus value (free market worth minus actual salary) around $12 million. In other words, he has been a valuable asset in the Padres bullpen, providing performance that would be highly valued on the free agent market, and simultaneously making peanuts.

The good news for the Padres is that Gregerson does not hit arbitration until 2012, and he is under control through 2014. If he continues performing anywhere near this level, the Khalil Greene to St. Louis trade is going to turn into a major coup for the Padres, regardless of how Mark Worrell progresses.

While Gregerson’s performance has been excellent, what is perhaps even more interesting is just how he has done it. The right hander has succeeded primarily with two pitches, the fastball and the slider. In fact, this year Gregerson has resorted to the slider a gasp-inducing 61.2 percent of the time. According to the PITCHf/x data available at FanGraphs, in 2010 he has offered up the four-seamer about 26 percent of the time, the two-seamer on nine percent of his pitches, and a change-up four percent of the time. Last season, Gregerson delivered the slider somewhat less often (48 percent) and the four-seamer with more frequency (37 percent).

The Baseball Info Solutions pitch classification data, also located at FanGraphs, strongly agrees with the PITCHf/x data, which is a bit of a rarity, but perhaps not unexpected considering that it is relatively easy to differentiate a fastball from a slider.

Gregerson’s slider is his bread-and-butter pitch, and if you look at the pitch-type linear weights leader board at FanGraphs, his slider ranks sixth in all of baseball, behind the likes of Josh Johnson (a starter) and Carlos Marmol (a freak).

Further, Gregerson’s fastball (+1.70 runs per 100 pitches) and change-up (+4.52 runs/100) also look like plus pitches, although there is nothing particularly special about them (note, of course, that we are dealing with a very small sample here). When you have one nasty pitch, though, it tends to make secondary offerings look better, as hitters are left off-balance and guessing at what pitch to expect. Imagine Gregerson throwing five or six consecutive sliders on the outer half, and then firing a two-seamer at the inside corner.

Gregerson is not shy about this either, noting that, “Coaches say to use your fastball to set up other pitches. I do the reverse. I set up my fastball with my slider,” in an article by Jeff Passan. Making the hitters’ battle even more complicated is the fact that, according to Gregerson, they have not yet been able to decipher the spin on his slider, making it more difficult to figure out what is coming—slider or fastball. To further investigate how Gregerson has succeeded with primarily a slider-fastball repertoire, let’s take a look at some PITCHf/x data (through July 7). First the standard pitch movement graph, which shows how much a pitch moves, in inches, when compared to a spin-less pitch (from the catcher’s perspective):


As the graphs clearly shows, the slider is most often pulled out of Gregerson’s arsenal. He also has your standard two and four-seam fastballs, and a few change-ups mixed in (the two pitches in the lower right hand corner are most likely curveballs, misclassified by the Gameday algorithm due to how infrequently they are thrown). We will concentrate on Gregerson’s slider now since it is the main reason for his dominance. His slider averages 83.6 miles per hour, with 3.3 inches of horizontal break and 2.0 inches of vertical break. However, as you can see from the above graph, there is a pretty wide variance in the pitch, with its speed ranging from about 81 mph to almost 86. Let’s take a look at how Gregerson attacks hitters with the slider:


Against righties, when going for the swing and miss, Gregerson primarily uses that sharp-breaking slider that starts toward the center of the plate and breaks off the table down and away. If hitters swing at this pitch, they generally miss. If they are able to lay off, it is probably going to be called a ball. You can see that hitters rarely swing and miss at a Gregerson slider if it is in the strike zone—either it is a called strike, a foul ball, or a ball in play.

The Incompleat Starting Pitcher
The end of the nine-inning start and how we got here.

When looking for the swing and miss versus lefties, Gregerson uses the same pitch he does against righties, except this time it breaks down and in to left handers. What is also interesting is that you can see a cluster of called strikes on the outside corner, backdoor sliders that initially appear outside but find the corner of the strike zone by the time they cross the plate. This pitch really is not available against righties because of the break of the slider. It is interesting how Gregerson attacks hitters from the opposite sides of the plate, and because he has been able to find a successful strategy against both righties and lefties, he is able to use his slider no matter which side of the plate the hitter is standing on.

Since I started writing this article, Gregerson’s ERA has jumped from 2.45 up to 3.00 (and it was already on the rise before that). This displays both the fickleness of a small sample size, the silliness of using ERA for relievers, and perhaps some of the expected regression that Gregerson was bound to encounter. However, even with the recent struggles, his peripheral numbers remain strong, and there is little doubt that he will remain an effective late-inning reliever.

So far in his career in San Diego he has been an excellent surprise, jumping from Double-A to the majors, and becoming a key anchor in one of the best bullpens in the game. It will remain to be seen whether he can continue to use a slider 60 percent of the time and both avoid injury and see continued dominance, but so far the Padres could not have asked for more. Chalk up another great trade to Kevin Towers during his reign in San Diego.

References & Resources
PITCHf/x data from MLBAM and Sportsvision, and downloaded using Joe Lefkowitz’s PITCHf/x tool.

Further reading: “Examining Luke Gregerson’s Slider,” “Should Luke Gregerson Change His Approach?,” “Hitters Can’t Square Up Gregerson’s Slider.”

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Dave Studeman
Dave Studeman

Great job, Myron.  Welcome to THT!

Mike Rogers
Mike Rogers

Nice work, Myron. Congrats on the gig at THT!

Myron Logan
Myron Logan

Much thanks, guys; thrilled about the opportunity to write here!

Nick, I remember thinking Gregerson was a nice addition to the deal, but I didn’t think he’d turn into a stud reliever so quickly.

Nick Steiner
Nick Steiner

Good piece Myron.  As a Cardinals fan who was originally a big fan of the Khalil trade, Gregorson’s success cuts particularly deep.