April 5, 2000

The Daily Prospectus

Juan Pena

by Joe Sheehan

Last Friday, the Red Sox announced that right-hander Juan Pena would miss the 2000 season with a torn medial collateral ligament in his right elbow. Pena will undergo Tommy John surgery and attempt to resume his career in 2001.

According to the team, the tear was caused when Pena took a line drive off his right wrist on March 25. Now, this would be a rather unusual way to suffer a torn elbow ligament, but the team's medical and front office staff have stood behind the explanation. They insist Pena showed no signs of elbow pain prior to the injury and that the only cause was the line drive.

Without calling that diagnosis into question, I'm going to present some evidence that perhaps the injury had a less dramatic, but no less damaging, cause. First, here's the comment on Pena from Baseball Prospectus 1997:

"Pena's a long way off radar, and just based on ability he has a
chance to be the name on everyone's lips in two years. The one negative,
and it's a big one, is that he averaged 7 1/3 innings a start this year, a
frightening number for a 19-year-old. He'll probably get hurt in the next
16 months. This idiocy will end when some 21-year-old whose arm falls off
sues and wins a monster worker's compensation award."

In 1996, Pena tore up the Midwest League, allowing less than a baserunner an inning and posting a 2.97 ERA in 26 starts. The workload seemed high at the time--it still does--but his injury made me want to know more. Since we don't have pitch counts for the Midwest League for 1996 (or 1999, for that matter), we'll have to estimate Pena's effort that year.

Enter Keith Woolner. Woolner is our resident database guru here at BP, and also operates and writes for the Stathead web site (www.stathead.com), featuring baseball research from around the Internet. He's worked extensively with Rany Jazayerli on the Pitcher Abuse Points metric. He generated a list of major-league pitchers who had seasons that most closely approximated Pena's innings pitched, hits allowed, walks allowed and strikeouts, while being used exclusively as a starter, and for whom we have pitch-count data.

PITCHER             Year  GS     IP    H  BB   SO    Pitches

Juan Pena           1996  26  187.2  149  34  156

Pascual Perez       1988  27  188.0  133  44  131       2427*
Ted Higuera         1990  27  170.0  167  50  129       2420*
Andy Ashby          1994  24  164.3  145  43  121       2179**
Alex Fernandez      1994  24  170.3  163  50  122       2554*
Francisco Cordova   1997  29  178.7  175  49  121       2539
Curt Schilling      1999  24  180.3  159  44  152       2658
John Smoltz         1999  29  186.3  168  40  156       2705

*  Missing pitch data for one start.
** Missing pitch data for two starts.

The seven pitchers on this list averaged 97.7 pitches per start (not counting the five starts for which we don't have pitch data). Obviously, we don't have that kind of precision, but I think we can say that Pena averaged between 95 and 100 pitches per start in 1996. That's an average, and it's as a 19-year-old.

Let's use Pitcher Abuse Points to get an idea of the kind of use Pena underwent in 1996. What follows is the PAPs accumulated by each of the above pitchers. Remember that "Workload" is PAP/start adjusted for age:

PITCHER            Year  Age  PAP   PAP/GS  Workload

Pascual Perez      1988   31  146     5.62       6.6
Ted Higuera        1990   31  232     8.92      10.4
Andy Ashby         1994   26  241    10.95      18.5
Alex Fernandez     1994   24  543    23.61      55.1
Francisco Cordova  1997   25  122     4.21       9.1
Curt Schilling     1999   32  557    23.21      23.2
John Smoltz        1999   32  145     5.00       5.0

The pitchers on this list averaged 283 PAPs over the course of the season, with a median PAP score of 232. Given that these were the pitchers whose performances most resembled that of Pena, it seems reasonable to assume he had comparable PAP data. If Pena's 1996 PAP had been this group's median PAP score of 232, Pena would have had a 1996 Workload of 28.3. That's a score that would have ranked him 17th in baseball in 1999, behind Sidney Ponson and ahead of Ryan Dempster.

There are a lot of approximations and assumptions here, but lacking actual pitch count data, I'm comfortable with what this tells me:

• Juan Pena averaged 7 1/3 innings per start in 1996. That's excessive for a 19-year-old.

• Pena's performance comps averaged around 95 pitches per start. That may be excessive for a 19-year-old.

• Pena's performance comps averaged 283 PAPs and had a median PAP score of 232. If Pena accumulated that many PAPs--if he even came close--then his workload was dangerous for a 19-year-old.

Whatever the immediate cause of Pena's injury, in my mind the real damage was done in 1996.

Joe Sheehan can be reached at jsheehan@baseballprospectus.com.

Joe Sheehan is an author of Baseball Prospectus. 
Click here to see Joe's other articles. You can contact Joe by clicking here