Low-A Hickory southpaw Martin Perez wields one of the best heaters in the Rangers' farm system. - Scott Lucas/The Ranger RundownWhen asked about Wilfredo Boscan, Rangers Minor League Pitching Coordinator Danny Clark said, "Well, the fastball is 89 [mph] or so, but I think that Boscan commands everything so well to both sides of the plate that makes up for it. His upside is big because of that. It's not all about velocity and he's still got some growing to do."

On the surface, the quote makes a lot of sense. A baseball thrown at 95 mph reaches home plate only two-hundredths of a second faster than a ball thrown at 90 mph and only three-hundredths of a second faster than a ball thrown at 88 mph. Perhaps those of us who like to track player development are too hung up on fastball velocity.

Looking to confirm the folly of fastball velocity, I used FanGraphs to capture the Pitch f/x data for all starting pitchers who logged at least 120 innings in 2008. The pitchers were sorted based upon the average velocities of their fastballs. I then took 10 player rolling averages (see explanation at bottom of article) of the ERAs, FIPs (fielding-independent ERA), K/9, BB/9, BAA, BABIP, HR/9, and LOB%. The results are presented in the three graphs below:

Contrary to expectations, there was a very strong correlation between fastball velocity and ERA. The ten starting pitchers with the highest fastball velocities had an average ERA of 3.70. Pitchers with fastball velocities of 90 mph or less had an average ERA of greater than 4.50. FIP follows essentially the same path as ERA. As one would expect, there was a very strong correlation between fastball velocity and strike-out rate. Surprisingly, there was very little difference between the walk rates of the pitchers who throw hard and those who do not. The consistency of the walk rate at approximately three walks per nine innings likely reflects a threshold of control that must be achieved for pitchers to succeed as starters at the major league level.

Given the correlation between fastball velocity and ERA/FIP/strikeout rate, it is not surprising that hitters have lower batting averages against starting pitchers with higher fastball velocities. As with the ERA graph, the batting average against (BAA) rises as fastball velocity decreases from 94 mph to approximately 90 mph, at which point the BAA remains relatively unchanged for the pitchers with fastball velocities below 90 mph. The variance in BAA appears to derive almost exclusively from strikeout rates, since the BABIP is essentially the same regardless of fastball velocity. The dip in both BAA and BABIP on the right-hand side of the graph results from Justin Duchscherer, whose 86 mph fastball produced a BAA of .211 and a BABIP of .240 in 2008.

Average home run rates and left-on-base percentages for pitchers classified by fastball velocity were plotted together, not because there is a correlation between the two but because they have similar values. The data indicates that pitchers with high velocity fastballs give up fewer home runs and are perhaps slightly more effective at stranding runners who get on base. These data contradict the notion that fastball velocity, at least among pitchers who become major league starters, is not that important.

For those of you who don't like graphical representations of data, some of the most interesting data from above is provided in tabular form below:

91 MPH IS A SIGNIFICANT INFLECTION POINT

One of the more interesting breakpoints in the data occurs at 91 mph. Thirty-six of the 46 pitchers (78 percent) with average fastball velocities above 91 mph in 2008 had ERAs below 4.00. In contrast, only 19 of the 60 pitchers (31 percent) with fastball velocities below 91 mph had ERAs below 4.00. The average ERA for pitchers with average fastball velocities above 91 mph was 3.69 in 2008, while the average ERA for the remaining pitchers was 4.37. As with the graphs and table above, it is difficult to deny the very strong correlation between fastball velocity and the performances of major league starting pitchers.

FASTBALL VELOCITY, TOP-OF-THE-ROTATION STARTERS, AND PITCH USE

To move this from a population study to a consideration of individual pitchers, I sorted the pitchers using FIP and placed them into groups of 30. In theory, the top 30 pitchers could be considered No. 1 pitchers for 2008, the next 30 could be considered No. 2 pitchers, and so on. The average fastball velocities and pitch use for the No. 1, No. 2, No. 3 and No. 4 pitchers are presented in the table below.

[CU = Change-up; Other = curveball + slider + cutter + knuckleball + undetermined]

As expected, almost all of the pitchers with FIPs that are among the top 30 in the league had average fastball velocities above 91 mph. The five outliers were Derek Lowe, Brandon Webb, Cliff Lee, Cole Hamels, and Justin Duchscherer. Lowe and Webb rely on outstanding sinkers, while Lee and Hamels have very good secondary pitches. Duchscherer is an outlier on the list, though it is worth noting that he used his fastball less than 44 percent of the time in 2008, which is significantly below the 60 percent fastballs that the rest of the group used.

Of the 21 pitchers with fastball velocities above 91 mph who were ranked outside the top 30 in FIP in 2008, the majority have relatively little major league experience. Matt Garza, Ricky Nolasco, Felix Hernandez, Ubaldo Jimenez, Justin Verlander, Matt Cain, Manny Parra, Nick Blackburn, Ian Snell, Johnny Cueto, and Edwin Jackson are presumably still trying to figure out how to be effective against major league hitters. Consistent with that notion, Hernandez, Jimenez, Verlander, Cueto, and Jackson are all having very good 2009 campaigns.

Interestingly, there is not a lot of variance in pitch use by any of the groups of pitchers. Major league pitchers tend to average 58 percent fastballs, 30 percent breaking balls, and 12 percent change-ups regardless of whether they are top- or back-of-the-rotation types. An exception is the group of pitchers with fastballs that average greater than 91 mph but whose FIPs place them in the bottom half of pitchers. The high-velocity, ineffective pitchers averaged 72 percent fastballs in 2008, suggesting that ineffective secondary pitches are likely limiting their ability to succeed.

SUMMARY

Succeeding as a major league pitcher clearly requires more than a quality fastball. Command, control, pitch movement, and at least a couple of secondary pitches are all prerequisites for pitchers to become mainstays in a major league rotation. Among those pitchers who can master the elements of being a quality starter, fastball velocity is perhaps the most important factor in distinguishing the top-of-the-rotation types from those who are manning the No. 3, No. 4 and No. 5 slots.

AND FOR THOSE WHO WANT TO KNOW HOW THE RANGERS' STARTERS STACK UP ...

Of the current Rangers starters, Derek Holland (93.2 mph), Vicente Padilla (91.9 mph), Scott Feldman (91.0 mph), and Matt Harrison (91.0 mph) are all averaging at least 91 mph on their fastballs.

(1) Holland's fastball ranks in the top 20 among starters in the majors. He is using his fastball too much (75 percent), so developing his slider and change-up will likely be the key to becoming the top-of-the-rotation type that his fastball suggests that he can be.

(2) Padilla's high walk rate (4.3 BB/9) and pedestrian strikeout rate (4.7 K/9) suggest that he will continue to be an enigma despite having the fastball of a top-of-the-rotation pitcher.

(3) Feldman's mix of pitches (63 percent fastball, 8 percent change-up, 29 percent other) and walk rate (3.0 BB/9) are about right. Like the rest of the Rangers' starters, his strikeout rate is low (4.7 K/9), though that has yet to impact his effectiveness.

(4) According to Pitch f/x, Harrison is throwing five different pitches (four-seamer, two-seamer, curveball, change-up, cutter). His control has been very good (2.9 BB/9), though his inability to strike hitters out (4.8/9) remains a cause for concern.

Among the many Rangers prospects, Neftali Feliz, Martin Perez, Michael Main, Blake Beavan, and hopefully Tanner Scheppers appear to be on their way to having the pieces necessary to be top-of-the-rotation type starters.

(1) Feliz's fastball will likely have him at the top of the list when he graduates to the majors. Becoming a quality major leaguer will require that he develop two secondary pitches that he can use in 30-40 percent of his offerings. Feliz also needs to improve his control so that he can reduce his walk rate from the 4.6 walks per nine innings that he has produced this year in AAA-ball.

(2) Despite being just 18 years old, Martin Perez apparently has two of the four elements of a top-of-the-rotation starter -- a fastball that is reaching the mid-90s and a swing-and-miss curveball. An improved change-up and improved control (Perez is currently walking 3.5 batters per nine innings at Low-A Hickory) are on the short list of things that he needs to master.

(3) Reports from the 2008 Fall Instructional League had Main throwing three quality pitches. His low-90s fastball would likely allow him to exceed the 91 mph threshold that separates many very good major league pitchers from those who are merely adequate. Consistency and control appear to be the two factors that separate Main from a major league career.

(4) Reports indicate that Beavan is now consistently throwing a four-seamer at 91-93 mph. He already has the control of a major leaguer (2.0 BB/9). If he is able to add a consistent slider and change-up to his 91-plus mph four-seamer and quality two-seamer, then Beavan looks to have the stuff and control of a quality major league starter.

(5) He's not in the system yet, but Scheppers' mid-90s fastball and plus slider/curveball are the stuff of a future No. 1 pitcher. Scheppers walked 4.3 batters per nine innings in his last year in college, so improved control will likely be among the most important developmental milestones for the big right-hander once he joins the Rangers' system.

[Rolling Averages: The rolling averages used to produce the first three graphs used stats from ten pitchers at a time. The first group of ten pitchers comprised those who had the ten highest fastball velocities. The second group comprised the pitchers with the 2nd through 11th highest fastball velocities. The third group comprised the pitchers with the 3rd through 11th highest fastball velocities. And so on through the final group which comprised pitchers with the ten lowest fastball velocities among qualifying starters in 2008.]