Tampa Bay Rays

MLB Fact or Fiction: Verducci Effect for David Price, Mat Latos and Phil Hughes?

Tom Verducci, co-founder of the "Verducci Effect."
Tom Verducci, co-founder of the "Verducci Effect."Andrew H. Walker/Getty Images
Andrew SeifterContributor IJanuary 28, 2011

On Jan. 11, Sports Illustrated senior writer Tom Verducci published his list of pitchers at risk of the "year after effect"—or "Verducci Effect"—in 2011.  The Verducci Effect, a theory put forth by Verducci and former Oakland A's pitching coach Rick Peterson more than a decade ago, posits that pitchers under 25 years old whose workloads increase by more than 30 innings are at risk of injury or major regression the following season. 

Verducci's 2011 list of young pitchers at risk includes such notable names as the Rays' David Price, the Padres' Mat Latos, the Yankees' Phil Hughes and Ivan Nova, the Giants' Madison Bumgarner, the Reds' Travis Wood, the A's Gio Gonzalez and the Blue Jays' Brett Cecil.

Verducci's theory has become conventional wisdom accepted by many of the most respected minds in baseball.  For instance, when Verducci released his red flag list for 2010, he quoted A's general manager Billy Beane as saying "We always keep an eye on the Verducci metrics."

And yet Verducci's 2010 list of risky pitchers included four players who went on to have not just good, but excellent seasons: the Mariners' Felix Hernandez, the Marlins' Josh Johnson, the Tigers' Max Scherzer and the Padres' Latos, who has now appeared on the list two consecutive years. 

Verducci acknowledged that the performance of these four stars was "as strong a showing against the Verducci Effect since I started tracking it," but he insisted that the Verducci Effect has not "gone away."

He pointed to four other pitchers on his 2010 list (the Padres' Cesar Carrillo, the Astros' Bud Norris, the Reds' Homer Bailey and the Tigers' Rick Porcello) who "were hurt or regressed" the following season, and argued that the remaining two names on his list (the Yankees' Joba Chamberlain and the Rays' Wade Davis) "had so-so results."  He added that the performances of Hernandez, Johnson and Scherzer prove his long-held belief that "the risk is much lower for bigger-bodied pitchers who are at the older end of the age spectrum."

Maybe so, but the main thing Verducci's 2010 list clearly demonstrates is that a young pitcher is not guaranteed to get injured or pitch poorly the year after he sees a significant increase in innings.  That doesn't mean the Verducci Effect should necessarily be dismissed completely, though. 

To get a better sense of how to evaluate the Verducci Effect, let's consider how all of the pitchers that have made Verducci's list over the last four seasons have gone on to perform the following year.  For the sake of simplicity, we will only consider a player's major league numbers and won't count playoff statistics (Verducci does include playoff innings in his analysis).

Below is the complete list for 2007, 2008, 2009 and 2010, with the year the player appeared on Verducci's red flag list in parentheses followed by the pitcher's performance the season immediately before and the season immediately after appearing on the list:

Cole Hamels ('07)

Before Verducci Effect: 132.1 Innings, 145 Ks, 4.08 ERA, 1.25 WHIP /// After Verducci Effect: 183.1 Innings, 177 Ks, 3.39 ERA, 1.12 WHIP


Justin Verlander ('07)

 186 IP, 124 Ks, 3.63 ERA, 1.33 WHIP  ///  201.2 IP, 183 Ks, 3.66 ERA, 1.23 WHIP


Anibal Sanchez ('07)

 114.1 IP, 72 Ks, 2.83 ERA, 1.19 WHIP  ///  30 IP, 14 Ks, 4.80 ERA, 2.07 WHIP


Jered Weaver ('07)

 123 IP, 105 Ks, 2.56 ERA, 1.03 WHIP  /// 161 IP, 115 Ks, 3.91 ERA, 1.39 WHIP


Sean Marshall ('07)

 125.2 IP, 77 Ks, 5.59 ERA, 1.52 WHIP  ///  103.1 IP, 67 Ks, 3.92 ERA, 1.37 WHIP


Scott Olsen ('07)

 180.2 IP, 166 Ks, 4.04 ERA, 1.30 WHIP  ///  176.2 IP, 133 Ks, 5.81 ERA, 1.76 WHIP


Jeremy Bonderman ('07)

 214 IP, 202 Ks, 4.08 ERA, 1.30 WHIP  ///  174.1 IP, 145 Ks, 5.01 ERA, 1.38 WHIP


Adam Loewen ('07)

 112.1 IP, 98 Ks, 5.37 ERA, 1.54 WHIP  ///  30.1 IP, 22 Ks, 3.56 ERA, 1.75 WHIP


Anthony Reyes ('07)

85.1 IP, 72 Ks, 5.06 ERA, 1.38 WHIP  ///  107.1 IP, 74 Ks, 6.04 ERA, 1.41 WHIP


Scott Mathieson ('07)

 37.1 IP, 28 Ks, 7.47 ERA, 1.71 WHIP  ///  No Major League innings (only 8 Minor League innings)


Boof Bonser ('07)

100.1 IP, 84 Ks, 4.22 ERA, 1.28 WHIP  ///  173 IP, 136 Ks, 5.10 ERA, 1.53 WHIP


Ian Kennedy ('08)

 19 IP, 15 Ks, 1.89 ERA, 1.16 WHIP  ///  39.2 IP, 27 Ks, 8.17 ERA, 1.92 WHIP


Fausto Carmona ('08)

 215 IP, 137 Ks, 3.06 ERA, 1.21 WHIP  ///  120.2, 58 Ks, 5.44 ERA, 1.62 WHIP


Ubaldo Jimenez ('08)

 82 IP, 68 Ks, 4.28 ERA, 1.30 WHIP  ///  198.2 IP, 172 Ks, 3.99 ERA, 1.43 WHIP


Tom Gorzelanny ('08)

 201.2 IP, 135 Ks, 3.88 ERA, 1.40 WHIP  ///  105.1 IP, 67 Ks, 6.66 ERA, 1.80 WHIP


Dustin McGowan ('08)

 169.2 IP, 144 Ks, 4.08 ERA, 1.22 WHIP  ///  111.1 IP, 85 Ks, 4.37 ERA, 1.37 WHIP


Chad Gaudin ('08)

 199.1 IP, 154 Ks, 4.42 ERA, 1.53 WHIP  ///  90 IP, 71 Ks, 4.40 ERA, 1.32 WHIP


Yovani Gallardo ('08)

 110.1 IP, 101 Ks, 3.67 ERA, 1.27 WHIP  ///  24 IP, 20 Ks, 1.88 ERA, 1.25 WHIP


Jon Lester ('09)

 210.1 IP, 152 Ks, 3.21 ERA, 1.27 WHIP  ///  203.1 IP, 225 Ks, 3.41 ERA, 1.25 WHIP


Cole Hamels ('09)

 227.1 IP, 196 Ks, 3.09 ERA, 1.08 WHIP  ///  193.2 IP, 168 Ks, 4.32 ERA, 1.29 WHIP


Chad Billingsley ('09)

 200.2 IP, 201 Ks, 3.14 ERA, 1.34 WHIP  ///  196.1 IP, 179 Ks, 4.03 ERA, 1.32 WHIP


Tim Lincecum ('09)

 227 IP, 265 Ks, 2.62 ERA, 1.17 WHIP  ///  225.1 IP, 261 Ks, 2.48 ERA, 1.05 WHIP


Clayton Kershaw ('09)

 107.2 IP, 100 Ks, 4.26 ERA, 1.50 WHIP  ///  171 IP, 185 Ks, 2.79 ERA, 1.23 WHIP


Dana Eveland ('09)

 168 IP, 118 Ks, 4.34 ERA, 1.48 WHIP  ///  44 IP, 22 Ks, 7.16 ERA, 2.18 WHIP


Mike Pelfrey ('09)

 200.2 IP, 110 Ks, 3.72 ERA, 1.36 WHIP  ///  184.1 IP, 107 Ks, 5.03 ERA, 1.51 WHIP


John Danks ('09)

 195 IP, 159 Ks, 3.32 ERA, 1.23 WHIP  ///  200.1 IP, 149 Ks, 3.77 ERA, 1.28 WHIP


Jair Jurrjens ('09)

 188.1 IP, 139 Ks, 3.68 ERA, 1.37 WHIP  ///  215 IP, 152 Ks, 2.60 ERA, 1.21 WHIP


Jon Niese ('09)

 14 IP, 11 Ks, 7.07 ERA, 2.00 WHIP  ///  25.2 IP, 18 Ks, 4.21 ERA, 1.40 WHIP


Cesar Carillo ('10)

 10.1 IP, 4 Ks, 13.06 ERA, 2.71 WHIP  ///  No Major League Innings (151 IP in AAA)


Bud Norris ('10)

 55.2 IP, 54 Ks, 4.53 ERA, 1.51 WHIP  ///  153.2 IP, 158 Ks, 4.92 ERA, 1.48 WHIP


Mat Latos ('10)

 50.2 IP, 39 Ks, 4.62 ERA, 1.30 WHIP  ///  184.2 IP, 189 Ks, 2.92 ERA, 1.08 WHIP


Joba Chamberlain ('10)

 157.1 IP, 133 Ks, 4.75 ERA, 1.54 WHIP  ///  71.2 IP, 77 Ks, 4.40 ERA, 1.30 WHIP


Homer Bailey ('10)

 113.1 IP, 86 Ks, 4.53 ERA, 1.47 WHIP  ///  109 IP, 100 Ks, 4.46 ERA, 1.37 WHIP


Josh Johnson ('10)

 209 IP, 191 Ks, 3.23 ERA, 1.16 WHIP  ///  183.2 IP, 186 Ks, 2.30 ERA, 1.11 WHIP


Rick Porcello ('10)

 170.2 IP, 89 Ks, 3.96 ERA, 1.34 WHIP  ///  162.2 IP, 84 Ks, 4.92 ERA, 1.39 WHIP


Max Scherzer ('10)

 170.1 IP, 174 Ks, 4.12 ERA, 1.34 WHIP  ///  195.2 IP, 184 Ks, 3.50 ERA, 1.25 WHIP


Felix Hernandez ('10)

 238.2 IP, 217 Ks, 2.49 ERA, 1.14 WHIP  ///  249.2 IP, 232 Ks, 2.27 ERA, 1.06 WHIP


Wade Davis ('10)

 36.1 IP, 36 Ks, 3.72 ERA, 1.27 WHIP  ///  168 IP, 113 Ks, 4.07 ERA, 1.35 WHIP


There are obviously some things that are not captured in these numbers, the biggest being that they don't account for minor league statistics.  But these statistics still tell a lot about whether to be concerned with the Verducci Effect or to take it with a grain of salt.

To better understand the data, let's break these pitchers down into four categories:


  1. Pitchers who had serious arm-related injuries the year after appearing on the Verducci Effect list
  2. Pitchers who dramatically regressed the year after appearing on the Verducci Effect list
  3. Pitchers who either improved, performed about the same or slightly regressed after appearing on the Verducci Effect list
  4. Pitchers who—whether due to serious non-arm injuries or being sent to the Minors—did not pitch at least 50 Major League innings in both the season before and after appearing on the Verducci Effect list

"Serious" injuries will be defined as injuries that require major surgery.  "Dramatic regression" will be defined as having an ERA that increased by more than 1.00 AND a WHIP that increased by more than 0.15 from the season before they were included on the list. 

Keep in mind that young pitchers often have success when they initially enter the majors but then struggle to make adjustments, an explanation for some regression that has nothing to do with inning totals.  It's more likely that the regression has to do with physical wear and tear if the pitcher completely falls apart.  Also, pitchers who dramatically improve their performance will be lumped in with pitchers whose performances stay the same because any improvement is unlikely to be caused by increased inning totals.

Here is how the Verducci list pitchers from the last four years break down:

Three Verducci Effect pitchers suffered serious arm-related injuries the following season: Sanchez, Loewen, and McGowan


Six Verducci Effect pitchers dramatically regressed the following season: Weaver, Olsen, Carmona, Gorzelanny, Hamels ('09) and Pelfrey


Twenty-two Verducci Effect pitchers either improved, stayed the same or slightly regressed the following season: Hamels ('07), Verlander, Marshall, Bonderman, Reyes, Bonser, Jimenez, Gaudin, Lester, Billingsley, Lincecum, Kershaw, Danks, Jurrjens, Norris, Latos, Chamberlain, Bailey, Johnson, Porcello, Scherzer and Hernandez


Six Verducci Effect pitchers did not pitch enough major league innings in one or both seasons to make the evaluation meaningful (These pitchers either suffered serious non-arm injuries or were sent to the minors for performance-based reasons): Kennedy, Gallardo, Eveland, Niese, Carillo and Davis


*Scott Mathieson is not included in any category, since he had already had elbow surgery during the 2006 season—before he was included on Verducci's 2007 list.


These groupings aren't meant to be perfect, they're just meant to give a sense of what has typically happened to pitchers who have appeared on the Verducci list.  And the results seem fairly clear. 

Of the 31 pitchers who were listed on the Verducci Effect list during the last four years and pitched enough major league innings to be evaluated, 22 pitchers—nearly 71 percent—either improved, stayed the same or slightly regressed from the year before they were put on the list. 

Only six pitchers—about 19 percent—dramatically regressed the year after an innings spike put them on Verducci's list.  And just three pitchers—less than 10 percent—suffered serious arm injuries after being placed on the Verducci Effect list.

Of course, it's hard to fully understand the implications of these numbers without knowing the frequency of injury and severe regression among pitchers who were not on Verducci's list, which would be a much more time-intensive exercise.  Four years is also a relatively small sample size.

But even when taking those issues into account, these numbers suggest that the majority of pitchers who appear on Verducci's list are likely to be just fine following their jump in innings the previous year, and those that run into problems are more likely to have performance issues than severe health issues. 

Whether you're a fantasy manager that is considering whether to draft Mat Latos or a Tampa Bay Rays fan counting on David Price to anchor your rotation this year, you may still want to take the Verducci Effect into account.  The Billy Beanes of the world still do, after all.  But you can also take comfort in the fact that being on the list appears to be a bit less risky than it might seem. 

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