Fastball 101: Lefties And Relievers

After taking a look last week at the hardest-throwing starting pitching prospects in the 2008 Prospect Handbook, let’s dive right into relievers and lefthanded starters.

We’ll start with the lefthanders, since starting pitchers tend to be more interesting and have higher ceilings than minor league relievers. Looking at the list of hardest-throwing prospects from the 2008 Handbook shows just four lefthanders among the 23 pitchers (17 percent). According to, among the 666 pitchers who appeared in a major league game last year, 185 were southpaws, or 28 percent. That difference doesn’t seem particularly out of line given that even casual fans know that righthanded starters usually throw a few ticks harder than their lefty counterparts.

This point is hammered home by Baseball Info Solutions, which noted that from 2005 to 2006 just 29 percent of lefthanders in the major leagues threw their fastballs, on average, at 90 mph or above, whereas 63 percent of righthanders averaged at least 90 mph with their fastballs.

Lefthanders are more scarce in the general population, yet they are vital in roster construction for a manager to take advantage of match-ups against lefthanded-hitting batters. With demand exceeding supply, talent evaluators and general managers can’t afford to hold a lefty’s fastball to the same standard as a righthander’s. That’s why you will read some scouting reports in the Handbook that say a pitcher has "plus velocity from the left side" or "enough velocity for a lefty."

The following is a list of the hardest-throwing lefthanders who appear in the Handbook, sorted by their peak velocities. A pound sign (#) signifies that a pitcher missed either most or all of the 2007 season due to injury or will miss the 2008 season. Statistics are aggregate minor league totals from the 2007 season, and ages are as of Sept. 1, 2007.

Aaron Poreda CWS 20 100 9.3 1.9 46 R
Clayton Kershaw LAD 19 99 12.0 4.9 122 LoA/AA
Franklin Morales COL 21 98 7.4 4.6 113 AA/AAA
Jake McGee TB 21 98 11.3 3.3 140 HiA/AA
Madison Bumgarner SF 18 97 N/A N/A N/A N/A
Kasey Kiker TEX 19 97 10.5 3.8 96 LoA
Gio Gonzalez OAK 21 96 11.1 3.4 150 AA
Sean West# FLA 21 96 N/A N/A N/A N/A
Scott Elbert# LAD 22 96 15.4 6.4 14 AA
Ross Detwiler WAS 21 96 7.6 3.2 33 R/HiA

Clayton Kershaw, Jacob McGee, Franklin Morales and Gio Gonzalez all ranked in Baseball America’s Top 100 prospects list in 2007 and figure to do so again this year. Ross Detwiler and Madison Bumgarner were both top-10 picks in the 2007 draft, while Aaron Poreda went later in the first round. Kasey Kiker was a first-rounder in 2006 and just struck out 10.5 batters per nine in the low Class A Midwest League. West and Elbert have seen their stocks decline since having season-ending labrum surgeries in 2007, but Elbert was a first-rounder in 2004 and West was a supplemental first-rounder in 2005. (Elbert’s surgery wasn’t to repair a tear in the labrum, like West’s, but rather to remove scar tissue.)

Poreda is the hardest-throwing lefthander in the minors, although deductive reasoning using last week’s list should have made that obvious. His power sinker helped induce 3.14 groundouts for every fly out in the Pioneer League. That figures as a 76 percent groundout rate—though in a limited sample size of just 87 batted ball outs. Whether he develops a plus secondary offering is questionable given his arm action.

Bullpen Blazers

Relievers have an edge over starters because they typically pitch in one-inning stints, allowing them to pitch at their peak velocities without worrying about pacing themselves for several innings. This is a key reason why starters generally lower their ERAs when they convert to relievers, even though nothing has changed about them fundamentally. The authors of “The Book” found a difference of about one run in ERA when a starting pitcher became a reliever, primarily due to an increase in his strikeout rate. After all, fewer batted balls translates into fewer chances for hits or errors, thus fewer run-scoring opportunities. The authors also found that convenional wisdom is correct: Relievers have an advantage over starters because they don’t have to face the same batters multiple times in a game.

In the Prospect Handbook, it’s difficult for a relief pitcher to make a team’s top 10. Dominant major league relievers are often starters in the minor leagues, and minor league relievers often have limited ceilings. Their opportunity to contribute in the major leagues is limited because they throw so many fewer innings than starters do. Dominant relievers such as Jonathan Papelbon, Mariano Rivera, Joe Nathan, Billy Wagner, J.J. Putz and Jason Isringhausen have been incredibly valuable, but all were starters for the majority of their minor league careers.

Those who do crack a team’s Top 30 usually have had success at a high level of the minors and are on the verge of cracking a team’s 25-man roster, or they have a great fastball. Most relievers in the Handbook touch at least 95 mph, and a greater proportion of relievers than starters in the book top out in the high 90s.

  95+ 97+
Starters 31.1% 12.0%
Relievers 56.6% 22.1%

Of course that’s selective sampling at its finest, as there are far more starters in the book than there are relievers, and only the best of those relievers will get a ranking. Having a plus-plus fastball is one way for a relief prospect to make the book, though several other factors can help a relief pitching prospect, such as a deceptive delivery or pitch, a unique arm angle, a high-percentage of strikes thrown, a proclivity for inducing ground balls or a pronounced platoon split.

Here are the hardest-throwing relievers according to peak velocity who appear in the Handbook. An asterisk (*) denotes a lefthander.

Juan Morillo COL 23 101 9.5 4.2 67 AA/AAA
James Hoey BAL 24 100 13.6 2.8 46 AA/AAA
Dennis Sarfate BAL 26 100 9.9 6.9 62 AAA
Daniel Stange ARI 21 99 10.7 3.7 49 HiA/AA
Bob McCrory BAL 25 99 8.8 5.6 45 HiA/AA
Jose Ceda CHC 20 99 12.4 6.1 50 R/LoA
Matt Bush# SD 21 99 20.0 2.5 8 R/LoA
Merkin Valdez# SF 25 99 N/A N/A N/A N/A
Luis Lebron BAL 22 98 14.1 8.7 58 LoA/AA
Billy Petrick CHC 23 98 8.3 2.0 54 HiA/AA/AAA
Josh Roenicke CIN 25 98 10.8 4.1 47 HiA/AA
Scott Nestor FLA 23 98 10.3 4.8 75 AA
Jose Mijares* MIN 22 98 10.5 6.9 70 AA/AAA
Jason Motte STL 25 98 10.5 3.5 59 HiA/AA

Most of these players are still learning how to make the transition from thrower to pitcher. Eight out of the 12 had a strikeout-per-nine rate in double digits. Yet only James Hoey and Billy Petrick walked fewer than three batters per nine innings.

Another interesting difference between this list and starting-pitcher list is that the average age of the relievers is 23.2 years old, which is nearly three years older than the starters. While there isn’t enough evidence here to make any conclusions, most of these relievers began their professional careers as starting pitchers. Since then, they have either struggled with their command or struggled to develop a secondary repertoire.

As alluded to last week, it’s likely that several of the hardest-throwing starters will one day end up relievers because of things such as their command, mechanics or health.

Rockies righthander Juan Morillo tops the list. The Rockies reportedly clocked Morillo as high as 104 mph in 2004, and he still routinely touches triple digits. After poor command plagued him throughout his minor league career, Morillo converted from a starter to a reliever in 2007.

The Orioles are heavily represented on this list, with a quarter of hard-throwing relievers. All four rank in the back half of the Orioles’ Top 30, with Bob McCrory leading the way at No. 16. He and Hoey have had Tommy John surgery already.

Jose Ceda, the youngest player on this list and the one with perhaps the most upside, has shifted between starting and relieving in his two professional seasons in the United States. He made seven starts in 23 games this year, but he finished the season as a reliever and flourished in that role. The Cubs appear content to keep him in the bullpen.

Yes, that’s Matt Bush, who went first overall to the Padres in the 2004 draft as a high school shortstop. They converted him to relief at the end of last season, after nearly three full seasons of limited offensive growth, and he touched 99 mph before having Tommy John surgery in September.

Lefthanded Relief

The list of power-armed southpaws in the bullpen is much smaller, with only six prospects reaching 95 mph.

Jose Mijares MIN 22 98 10.5 6.9 70 AA/AAA
Daniel Moskos PIT 21 97 9.2 3.5 16 R/SS
Leyson Septimo ARI 22 96 N/A N/A N/A N/A
Neal Musser KC 27 95 7.6 1.8 55 AAA
Jerry Blevins OAK 23 95 11.9 2.1 78 HiA/AA/AAA
Erick Threets SF 25 95 6.6 5.8 55 AAA

Daniel Moskos, the No. 5 overall pick in the 2007 draft, has the highest ceiling of the group. Moskos worked as both a starter and a reliever at Clemson, and while former Pirates general manager Dave Littlefield announced that the organization would groom Moskos as a reliever, there’s still a chance he could return to a starting role under new management. Jose Mijares flashes three above-average pitches, but he hasn’t shown the ability to throw strikes at an acceptable rate.

Neal Musser and Jerry Blevins both appear to be ready for a chance to stick in a major league bullpen. Septimo is a converted outfielder who hit 96 mph on the mound in instructional league. Erick Threets made an appearance atop last week’s list of the hardest throwers from the 2002 handbook, and his poor walk rate of 5.76 per nine innings last year in Triple-A was the first time he’s cut that number below six since that book was published.

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