Notice: Trying to get property 'display_name' of non-object in /var/www/html/wp-content/plugins/wordpress-seo/src/generators/schema/article.php on line 52
keyboard_arrow_uptop

The halfway mark of the season is a natural point to stop and reflect on the remarkable performances of the baseball calendar to date. We reviewed the best stuff among starting pitchers at the quarter-season mark, so let's now turn our attention to the guys who come out of the bullpen.

Relievers’ stuff tends to be even more electric than that of their starting counterparts, given the sprinter-like nature of the job in addition to the fact that a less-varied repertoire is par for the position. With this in mind, we’ll delve into the fastballs and sliders that define the reputations of some of the game's most electric arms. Once again, we kindly ask the readers to add their own opinions to the mix, voting for one hurler from each category to represent the best stuff in baseball for the first half of the 2013 season. Please cast your votes in the comments section. (All stats are through games of July 1.)

The Heat

(minimum 300 fastballs)

Aroldis Chapman

Pitch Count

Frequency

Avg Velo

Whiff/Sw %

HR %

Opp AVG

Opp SLG

514

84.3%

98.1 mph

32.2%

0.58%

.235

.367

It should come as no surprise to see Chapman's name at the top of the list. The lefty with the legendary 105 mph fastball may not be breaking his own record with his raw velocity this season, but his 98.1 mph average fastball is still the tops in baseball, ranking second in the majors behind Kelvin Herrera's 98.4 mph average. That kind of velo is just unfair when it comes from a southpaw, particularly considering Chapman's excellent momentum and resulting extension at release point. His whiff/swing rate also ranks second in the game among pitchers with at least 300 pitches this season, behind only Ernesto Frieri's 33.1 percent mark. Chapman has used the four-seamer 99 percent of the time when he falls behind in the count (including a full 100 percent when behind against right-handers), but his predictability has done little to help opposing hitters to make solid contact.

Chapman’s slider has been even more effective in squelching opposing bats, as he’s yet to allow a hit off the pitch this season. He has registered zero walks in the 27 plate appearances that ended with a slide-piece, with a ridiculous whiff/swing rate of 57.5 percent on the pitch. The only thing keeping Chapman from making multiple appearances on the ballot are that his 95 sliders on the season fall short of the volume necessary for inclusion.

Steve Delabar

Pitch Count

Frequency

Avg Velo

Whiff/Sw %

HR %

Opp AVG

Opp SLG

502

71.3%

95.7 mph

30.1%

0.20%

.233

.322

Delabar gained notoriety for his late rise, ascending to the big leagues at 27 years old on the heels of an eight-mph uptick in fastball velocity. His whiff-per-swing rate on the fastball ranks just behind Chapman’s at third in the league among qualifying relievers, but what distinguishes Delabar's case from the rest is a track record of keeping the ball in the yard, with just a single homer allowed on more than 500 fastballs thrown this year. Pitchers typically give up more long balls on heaters than any other pitch type, and true to form, Delabar has not allowed any bombs on non-fastballs. His single homer surrendered speaks to the strength of his most dominant pitch, though his 71 percent fastball frequency is the lowest of the candidates.

Ernesto Frieri

Pitch Count

Frequency

Avg Velo

Whiff/Sw %

HR %

Opp AVG

Opp SLG

626

86.6%

94.9 mph

33.1%

0.96%

.207

.370

Frieri's raw velocity doesn't measure up to that of the other hurlers on this list, but his heater has secured more empty swings than any other reliever’s. He throws hard, but his exceptional performance has as much to do with deception as it does raw velo. Like Chapman, Frieri relies on plus momentum to create a deep release point, which allows the perceived velocity of his pitches to play up beyond the numbers on the radar gun. His big upper-body load not only takes the strain off of his throwing arm, but also acts to hide the baseball from the view of opposing batters, which combines with the extra release distance to invoke late swings from quality hitters who get a late read on the pitch despite Frieri's heavy fastball frequency.

Trevor Rosenthal

Pitch Count

Frequency

Avg Velo

Whiff/Sw %

HR %

Opp AVG

Opp SLG

538

80.1%

97.9 mph

29.6%

0.56%

.217

.330

The young Cardinal has been dominant in his second tour of the National League. His fastball has been his bread-and-butter, and he’s gone to the pitch more than 90 percent of the time on the first pitch of an at-bat. The 98 mph heat ranks just behind Chapman’s at no. 3 in terms of sheer velocity, fueling an Aroldis-esque strikeout rate of 34.8 percent, and Rosenthal's impeccable command of the pitch has led to an overall K-to-walk ratio of seven-to-one. Time will tell whether the right-hander eventually moves to the rotation, where he would likely have to sacrifice some fastball frequency in favor of a wider mix of pitches (unless he’s allowed to follow the two-pitch plan of teammate Shelby Miller).

The Slider

(minimum 150 sliders)

Al Alburquerque

Pitch Count

Frequency

Avg Velo

Whiff/Sw %

HR %

Opp AVG

Opp SLG

233

60.1%

86.7 mph

48.6%

0.00%

.137

.157

Though his overall line includes a number of red flags, Alburquerque continues to frustrate opposing hitters with his effectively wild approach. He makes the slider list as much for his usage pattern as the overall effectiveness of the pitch, with a ludicrous 60 percent frequency. The slider is his go-to offering with two strikes, as he throws the breaker greater than 75 percent of the time when a strikeout is on the menu.

After walking 13 batters in his first 14 innings, Alburquerque was sent to the minors in mid-May to try to work some of the LaLoosh out of his delivery, and though he continued to hand out freebies at a rate of almost one per inning in the minors, the Tigers decided to bring him back up to bolster a floundering bullpen at the big-league level. Detroit will live with the walks so long as the right-hander continues to use his hard slider to keep the ball out of reach of hitter hot-spots, as hard contact becomes extinct when his slide-piece makes an appearance.

Jason Grilli

Pitch Count

Frequency

Avg Velo

Whiff/Sw %

HR %

Opp AVG

Opp SLG

197

32.8%

83.5 mph

50.0%

0.00%

.152

.152

Grilli has been one of the most dominant relievers in baseball this season, contributing to a Pittsburgh 'pen that ranks as the best in the National League in terms of converting saves and stranding inherited runners. While the 36-year-old journeyman’s K-to-walk count of 57-to-7 is completely out of line with career norms, his 41.3 percent strikeout rate represents just modest bump from 2012's tally of 36.9 percent. The stinginess with the free pass is what stands out most in Grilli's stat line, along with just a single homer allowed in his 36.7 innings of work.

Grilli’s slider has been absolutely untouchable, inducing whiffs on exactly half of the swings that he’s generated from opposing batters. In fact, the next extra-base hit Grilli allows on the pitch will be his first of 2013. His whiff/swing rate ranks fifth in baseball among pitchers who have thrown at least 150 sliders this year, and the mark rises to second in the game if we raise the threshold to 180 sliders. The pitch is just vicious, with excellent depth in addition to the glove-side fade, as Mike Trout learned in his first encounter with Grilli just 10 days ago.

Sergio Romo

Pitch Count

Frequency

Avg Velo

Whiff/Sw %

HR %

Opp AVG

Opp SLG

226

44.1%

78.5 mph

45.8%

0.00%

.121

.167

Romo relies heavily on his slider to generate outs against big-league hitters, and right-handed batters can nearly be assured of seeing the pitch with two strikes given Romo's 72 percent slider usage in such situations. That rate is actually down from last season's frequency of 85 percent versus righties with two strikes, a prevalence that became famous after Romo was able to catch Miguel Cabrera looking at a belt-high fastball at 89 mph to end the 2012 World Series.

Romo’s slider rate was 58 percent overall last year, and despite a decreased reliance on the pitch in 2013, Romo has been able to silence opposing bats while still maintaining a heavy dosage of his best offering, which earns a slider label based more on its sideways tilt than its curve-like velocity. Batters just cannot lay off the pitch, as evidenced by a 32-to-2 strikeout-to-walk ratio in plate appearances that culminate with the slide-piece. For further proof, just ask Giancarlo Stanton how he felt after this vintage Romo slider on June 22:

Greg Holland

Pitch Count

Frequency

Avg Velo

Whiff/Sw %

HR %

Opp AVG

Opp SLG

196

32.6%

88.6 mph

55.5%

0.51%

.085

.170

Holland throws one of the hardest sliders in the game, coming in at almost 89 mph on average and ranking behind only the slider of Bryan Morris on the velocity chart. The pitch has late bite that disguises its identity until deep in the flight path, and the sharp downward break fools batters into swings that are triggered toward heat but miss over the top. His whiff-per-swing rate on the slider ranks third in baseball among qualifying pitchers, and though he is the only pitcher on this list who has surrendered a homer on his slider, the .085 opponents average (4-for-47) on the pitch is the best mark of the group. Holland’s 2013 K rate is an astounding 42.7 percent, with 31 of his 58 total strikeouts coming via the slider and allowing him to anchor the American League’s best relief corps.

Thank you for reading

This is a free article. If you enjoyed it, consider subscribing to Baseball Prospectus. Subscriptions support ongoing public baseball research and analysis in an increasingly proprietary environment.

Subscribe now
You need to be logged in to comment. Login or Subscribe
ddietz2004
7/03
FB - Chapman
SL - Grilli
rawagman
7/03
Chapman & Romo, please
chabels
7/03
Chapman and Holland. Romo's looks like it could flatten out and become gopher bait.

Any mechanical reason that nine of these ten guys are RHP? (where only ~70% of MLB pitchers are RHP)
tombores99
7/04
Criteria were largely statistical, based on PITCHf/x, along with a strong dose of subjectivity. I leaned heavily on whiff/swing % and opponents' SLG, as well as velo for fastballs [and Holland's slider]. I also looked at pitch frequency with added weight, for reasons of sample size as well as an indicator of a pitcher achieving great results while not necessarily surprising anyone with the pitch selection.

Any RHP/LHP trends were purely coincidental. That said, I should note that it was 7 of 8 guys who were RHP, not 9 of 10. Replace one RHP with a LHP and it falls right in line with expectations based on the population.
OsandNattyBohs
7/05
FB- Chapman, it's just not even a question.

SL- Grilli. More bite than a great white.