April 5, 2000
The Daily Prospectus
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 2705The 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 5.0The 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:
Whatever the immediate cause of Pena's injury, in my mind the real damage was done in 1996.
Joe Sheehan can be reached at firstname.lastname@example.org.