What's In A Number?

Thursday, February 24 2005 @ 08:00 AM EST

Contributed by: Jonny German

Among baseball's many commonly used terms are things like "Staff Ace", "Solid #3 starter", and "Back of the rotation guy". But as with many baseball terms, these can mean very different things to different people. As the Blue Jays look ahead to 2005, few would question Roy Halladay as a legitimate Staff Ace. But is Ted Lilly a Solid #3? Josh Towers is certainly not a front of the rotation starter, but is he a liability or an asset at the back?

To come up with empirical definitions for the #1 through #5 starting pitcher labels, I had a look at data from the last three seasons in both leagues. I chose three years of data rather than a larger sample to be sure my numbers apply to the current game (in terms of offensive levels, player conditioning, bullpen management, etc.). I wanted a sample larger than just one season to avoid excessive influence of the number and significance of injuries and call-ups in a given year.

This leads to what I feel is a very key point. As stated above, Roy Halladay is generally acknowledged as a #1 starter – but in 2004, his performance was surely not that of a #1, as he missed significant time and pitched at a reduced level for health reasons. While we expect that Roy will be back to his previously established performance standard for next year, our general definition of a #1 starter must take into account the fact that several starting pitchers we expect to be aces in 2005 will be hampered by injury. Further, in any given year there are rookies who make significant contributions. While only the most optimistic Toronto fan would have projected David Bush as a #3 Major League starter in 2004 before the season began, we shall see that in retrospect he wears that label handsomely.

Running The Numbers

As mentioned, I looked at 3 years of data to come up with my empirical definitions of the starting pitcher labels. I used Baseball Prospectus’ Value Over Replacement Player (VORP) as the yardstick for net performance. The top 90 starting pitchers from this period make up the definition of a #1 Starter; those ranked 91 through 180 define a #2 Starter; and so on.

In determining the top 450 starters over the past 3 years, one must of course draw a line to distinguish between starters and relievers. For the purposes of this study, the standard was defined as follows (note that the order is important):

  1. A pitcher with fewer than 12 starts is not a starter.
  2. A pitcher with 20 or more starts is a starter.
  3. A pitcher with more than 10 relief appearances is not a starter.

At this point the sample size was 454 pitcher-seasons. To arrive at the desired sample of 450, the 4 pitchers with the fewest innings pitched per game were dropped.

Without further ado, the results:

Pitcher GS IP H/9 BB/9 K/9 HR/9 ERA VORP
#1 Starter 32 213 8.1 2.6 7.2 0.9 3.27 55.0
#2 Starter 29 185 8.8 2.9 6.4 1.0 3.91 32.1
#3 Starter 27 163 9.2 3.1 5.9 1.1 4.31 20.3
#4 Starter 23 138 9.7 3.4 5.7 1.2 4.87 8.2
#5 Starter 22 123 10.4 3.8 5.6 1.4 5.76 -5.2

Table 1 – Major League starter expected performances. Total VORP: 110.4

[Note that the rate stats seen in Table 1 are roughly park- and league-neutral. This is because each is derived as the average of 90 different starters who are slotted not based on the rate stat itself, but on their genuinely context-independent VORP totals.]

As is to be expected given the structure of this study, the innings pitched totals seen here are lower than a team would look to receive from their starting pitchers, particularly at the bottom of the rotation. This is because it is exceedingly rare for a team to employ just 5 starters over the course of a full season. For example, in the past 3 years, the Blue Jays have averaged 11 different starters per season.

Typical Rotations

To get a better feel for what an average 5-man rotation produces, let’s have a look at a theoretical rotation for each Major League in 2004, with actual players representing each of the 5 slots.

Pitcher GS IP H/9 BB/9 K/9 HR/9 ERA VORP
J. Westbrook 30 216 8.7 2.5 4.8 0.8 3.38 54.4
Barry Zito 34 213 9.1 3.4 6.9 1.2 4.48 31.5
Joel Pineiro 21 141 9.2 2.8 7.1 1.3 4.67 20.4
Aaron Sele 24 132 11.1 3.5 3.5 1.1 5.05 7.4
R.A. Dickey 15 104 11.7 2.8 4.9 1.5 5.61 -4.6

Table 2 – Typical 2004 American League starting staff. Total VORP: 109.1

Before the season began, one might have reasonably projected Westbrook, Zito, and Pineiro as #1, #2, and #3 starters, but certainly not in that order. R.A. Dickey began 2004 strong, but reverted to his usual ways in due course. Many of us would have expected a #4 type performance out of Aaron Sele, but the Angels were doubtless hoping he would eat more innings.

Pitcher GS IP H/9 BB/9 K/9 HR/9 ERA VORP
Oliver Perez 30 196 6.7 3.7 11.0 1.0 2.94 54.5
Russ Ortiz 34 205 8.7 4.9 6.3 1.0 4.13 33.1
Eric Milton 34 201 8.8 3.4 7.2 1.9 4.75 18.7
Jae Seo 21 118 10.2 3.8 4.1 1.3 4.90 8.3
W. Obermueller 20 118 10.5 3.2 4.5 1.1 5.80 -4.5

Table 3 – Typical 2004 National League starting staff. Total VORP: 110.1

Oliver Perez made good on his considerable potential in 2004, turning in the 9th-best pitching performance in the National League at the age of 22 (Incidentally, his 23-year-old former teammate Jake Peavy in San Diego was 8th best with a VORP of 57.5). While many raised their eyebrows at the 4-year, $33 million contract that Russ Ortiz recently signed with the Diamondbacks, his performance in 2004 was in line with this type of compensation. We maintain our skepticism that Ortiz can continue to perform at this level. Eric Milton, on the other hand, will have to improve considerably to earn his new $8.5M per annum deal. A league-average rotation at that level of $/VORP would cost a cool 50 million dollars. Jae Seo (the NL’s answer to Josh Towers) was a representative #4 starter, while Wes Obermueller of Milwaukee turned in a typical #5 starter performance.

Your Toronto Blue Jays

Many have observed that starting pitching was not to blame for the abysmal 2004 Blue Jay season, and the numbers stand behind that opinion.

Pitcher GS IP H/9 BB/9 K/9 HR/9 ERA VORP
Ted Lilly 32 197 7.8 4.1 7.7 1.2 4.06 44.6
Roy Halladay 21 133 9.5 2.6 6.4 0.9 4.20 26.1
Miguel Batista 31 199 9.3 4.3 4.7 1.0 4.80 22.6
David Bush 16 98 8.8 2.3 5.9 1.0 3.69 20.6
Josh Towers 21 116 11.4 2.0 3.9 1.2 5.11 10.5

Table 4 – Blue Jays 2004 starting staff. Total VORP: 124.4

While pitching fewer innings than an average front five (743 to 823), the Blue Jay rotation contributed 14 more points of VORP than an average team would expect. If VORP theory holds, this lack of innings is inconsequential, as freely available talent can make up the 80 innings while contributing a VORP of zero. In practice, the 2004 Blue Jays netted a –2.7 Value Over Replacement Player from the other 5 men used as starting pitchers (without taking into consideration that some of these players spent time in the bullpen):

 +5.7	Gustavo Chacin
 +4.9	Ryan Glynn
 -0.5	Jason Kershner
 -1.4	Justin Miller
-11.4	Pat Hentgen

Ted Lilly has been variously described as a reasonable #3 starter to having the potential to be a #2 in 2005. The numbers see him differently: after hovering around the line between a #2 and a #3 in 2002 and 2003 (VORP totals of 23.4 and 28.8), Lilly’s 2004 VORP of 44.3 placed him in the bottom tier of #1 starters. At 29 years old and with a healthy past, I’m quite content to have him following Roy Halladay in the 2005 rotation. The only question with Halladay himself is if he’s entirely healthy and can remain so right through September. I like his chances.

The rest of the rotation brings yet more optimism for this observer. Assuming that management doesn’t continue the curious experiment of Miguel Batista in the bullpen, he’ll be the #3 starter. Despite some fans being ready to send him away for nothing by the end of the year, El Artista performed as a typical #3 when it was all said and done.

In contrast, Dave Bush contributed very similar value to Batista but was universally praised. Part of this was due to lower expectations, part due to the fact that he provided more quality and less quantity in innings pitched, and part due to his being the first J.P. Ricciardi-drafted player to have a Major League impact in Toronto. While the axiom says that young pitchers will break your heart, at 25 Bush’s pitching style is more savvy than showy.

Josh Towers finds himself at spring training with a host of challengers for his #5 starter title. He did the job just fine in 2004, but with his tragic flaw being the long ball he may be better suited to a more spacious home field. Waiting and eager to step in are Ryan Glynn, Gustavo Chacin, and Scott Downs. Further down the depth chart but also candidates to make Major League starts in 2005 are Chad Gaudin, Seung Song, and Josh Banks.