The Development of the 20-year-old Pitcher

Since 1995 the number of pitchers who saw big league action at age 19 or 20 has not been large.  We average no more than 3 such rookies each year.  What this means, in part, is less that Rick Porcello is in ‘elite’ company as it does that Rick Porcello is hard to find comparables for.  We understand the progression of pitchers in normal circumstances a bit better, those who enter the league at age 22 or 23 (like Tim Lincecum).  What we wonder about is whether we should expect greater development while in the majors from pitchers who get their start younger, like Porcello.  As a first stab at this, I’ve gathered the numbers for all the rookies who started at age 20 or younger since 1995 – limited to those who also played in the majors the next year (like Porcello) and their progression through their second and third seasons.

Since we can’t include the most recent additions, like Madison Bumgarner and Porcello himself, because they have not yet played their third major league campaign, the sample is limited to 25 pitchers spread over more than a decade starting with Jeff Suppan in 1995 up to Clayton Kershaw in 2008.  The list includes some stars, one old friend and some players you’ve probably never heard of:

Some things are obvious, Porcello is not in any way the same sort of pitcher as the Francisco Rodriguez‘s of the world – that isn’t critical. Jeff D’Amico isn’t a comparable we like to see (or even Bondo, at this point). We’d be thrilled, on the other hand, so see him follow the sort of career progression that someone like C.C. Sabathia did. Most of these pitchers were highly touted prospects and highly talented pitchers, it should be no surpise to see a number of greats on the list – those that aren’t cluster at the other end, textbook examples of potential unfulfilled.

Four of these pitchers, Jeff D’Amico, Gil Meche, Nick Neugebauer & Hayden Penn, did not play (in the majors) in that ‘3rd year’. Just a brief reminder that, perhaps to a greater degree than with other pitchers, there are risks that Rick Porcello could wind up a nonfactor on the 2011 Tigers due to injury. Looking at those who did play can tell us a bit: if we look at the median numbers for all the 20-year-olds we see a phenomenon very much like Porcello’s first two years: a median rookie ERA of 4.26 (often in limited playing time) that rose to 4.64 in their second year. Again Porcello, unfortunately, is an atypical case – many rookie pitchers were late-season call-ups. This makes it difficult to say whether these pitcher’s adjustment process between year 1 and 2 ought to be the same as Porcello. For lack of a valid alternative, I have assumed that it should. In year 3 we see an improvement, but not a tremendous one: to a median ERA of 4.57. This is very much in line with the Bill James’ projection for Porcello in 2011 – a movement in the direction of his 2009 numbers, but not an improvement on his career ERA.

If we confine ourselves to the other starters on the list, we get a different picture. A 1st year median ERA of 4.70, a 2nd year median of 4.26 and a 3rd year median of 3.65. Before you pooh-pooh those numbers as being indicitave of a Sabathia and not a Porcello bear in mind that average and median FIP and SIERA for groups much more closely tracks actual ERA for those groups than for individual players. Porcello was lucky in 2009, his ERA was 3.96 FIP was 4.77. In 2010 he, in some sense, pitched better – despite the rise in ERA to 4.92 his FIP fell to 4.31. If he follows the same progression as the rest of his fellow youngsters, an ERA under four is entirely possible – even likely. The reason that the full sample shows the sort of progression that makes us think grim thoughts about Porcello’s future is entirely among the relievers. Relievers were the ones that had the ‘second year curse’ which they struggled to recover from in their third season, probably because their stuff was a bit easier to hit once teams had them on film.

Median numbers are less biased by weights: the pitchers who pitched the most innings are likely the best, so averages can be dragged upwards towards the stars. Still, medians aren’t good for looking at some things. On average, these starters threw fewer innings overall in their second year and a higher percentage out of the ‘pen. For year 3, however, there was a significant increase in innings thrown and almost no bullpen appearances. Part of this may be that their innings were deliberately limited at ages 20 and 21, but the gloves began to be removed at age 22. In addition to losing the swingman role, they also increased their innings per start from 5.5 to almost 6.2. That’s not just due to increased pitch counts, they also decreased the number of pitches thrown per inning from 17.3 to 16 in year 3. Average walk rates fell from 10.6% to just under 9%. That was the big improvement from year 2 to year 3 – more efficiency allowing pitchers to go deeper into games. The other big improvement came from year 1 to year 2 – a decrease in isolated power. In other words, fewer bad mistakes badly punished. Average BABIPS did not fall, nor did strikeout rates rise.

Of course, there are many different paths Porcello could take. Some of those starters on the list who did not have a great second and third year did so for unique reasons – like Zack Greinke or Rick Ankiel. Barring his own unique implosion, what we might expect from Porcello is something more like Matt Cain‘s third campaign. Cain pitches in the national league, was more highly acclaimed than Porcello as a prospect, and may be the better pitcher. But he was also a bit of a ‘disappointment’ in his age 21 season, at least given how he pitched in his age 20 cup of coffee. He shaved half a run off his ERA and doubled his WAR in year 3 despite an unimpressive BABIP by walking fewer batters, getting hit less hard when he got hit and pitching deeper into ballgames.

I truly believe that Rick Porcello will not be an ace on this staff or any other unless he is able to move his strikeout rate closer to the 6.2 per 9 of his last stint in AAA. That he might do… or he might not. There’s nothing necessarily ‘natural’ about such a development. We know there is a lot of uncertainty and a lot of risk around Porcello this year. Like Brad Penny he could blow something out, or he could simply struggle. But if he’s able to do what the ‘median’ pitcher in his position (though that position is rather narrowly defined) or even the ‘average’ starter, he will improve in year three relative to year 2. Porcello’s year 1 was not as good as it looked, which skews our perspective. He did improve in year 2, and we can expect him to consolidate those gains in year 3. He’ll walk fewer batters still, throw fewer pitches, and do a better job of making sure that his fly balls stay in the park. His BABIP is not going to stay unluckily high, even if it never becomes his calling card a la Maddux – but he does not need to return to the exceptionally low BABIP of his rookie year to give us 3-4 WAR in 2011 instead of 2.