Pitching by the Numbers: Myth busting

Some very valuable fantasy baseball starting pitchers face being shut down for non-performance reasons due to some statistical snake oil that continues to con baseball executives long after it's been discredited by sabermetricians.

A big reason is that the man who "discovered" this bit of pseudo-science, Tom Verducci of Sports Illustrated, has a very big microphone and direct access top decision makers. The "Verducci Effect" says that young pitchers are more likely to get injured if they pitch more than 30 innings than the prior year. The term was coined by Will Carroll, formerly of Baseball Prospectus and now sharing the Sports Illustrated mantle with Verducci. To illustrate what an embarrassment it has become in the sabermetric community, Baseball Prospectus has scrubbed the definition that Carroll coined while writing there from its glossary. And my Yahoo! Friends & Family League colleague Derek Carty of Baseball Prospectus recently did a harsh takedown of the VE at BP (subscription may be required for the link).

I was early to the party in slamming it, but far from first. Big hat tip to David Gassko of the Hardball Times for his far earlier effort. Nonetheless, it continues to guide the thinking of MLB executives, who would do just as well following daily horoscopes instead. Before we summarize the case I made against it previously, let's look at the pitchers in most dire risk of early shutdown and what their limits would be if the Verducci Effect is followed to the letter.

Stephen Strasburg (110.3 innings in '12, 44.3 innings last year, Verducci says he should be shut down at 74.3 innings)
Chris Sale (117.7/71.3/101.3)
Felix Doubront (107/87.7/117.7)
Drew Smyly (82.3/126/156)

The idea that teams buy this nonsense is not conjecture on my part. Read Verducci himself just last week:

It's not just about Stephen Strasburg. All around baseball, as young pitchers break down, organizations search for ways to keep them healthy. Increasingly, one of those ways is to limit innings.

Verducci then glowingly talks about something really stupid that the Padres did in shutting down already – for the rest of the year – a top prospect (Donn Roach) pitching lights out baseball.

Let's summarize the key problems with the Verducci Effect:

Why is it even innings and not pitches, as we noted in this space before?

Why 30 innings and not 29 or 31? Because it's a round number? (Because that was the number that best supported the point that Verducci was trying to prove when he arbitrarily selected it.)

Why isn't it just injuries but also "poorer performance?" (Verducci does this to make the target larger so he can get a greater percentage of hits.)

What's wrong with including poorer performance as a "hit?" (Because regression should be expected of all young, relatively successful pitchers.)

But perhaps my favorite argument against Verducci was made by Advanced NFL Stats's Brian Burke.

Burke says that pitching injuries are inevitable. Over time, all pitchers have their arms decay. "Pitchers don't enter the major leagues hurt and gradually get healthier throughout their career."

He also uses the famous Monty Hall Problem to make a point that because the pitchers were healthy in Year 1 they necessarily are more likely to be injured in Year 2.

Burke argues that if pitchers have a 1-in-5 chance of getting hurt and you take one healthy year away looking back at a five-year sample, the odds now are 1-in-4 that the following year is an injury year. Depending on how someone looks at the data, the supposed increase in injury risk may be merely an illusion. Burke's point about entropy and pitching says that unhealthy is always more likely to follow healthy for pitchers regardless of whether they pitch 29 or 31 more innings than they did the year prior to the healthy season. The healthy year and next year are not independent like, say, two flips of a fair coin. But most damningly, despite all the emphasis on innings limits, pitchers – especially starters – are still getting hurt at an alarming rate. If Verducci's effect was correct, injuries should be decreasing due to so many teams limiting young pitcher's innings. After all, it's been widely publicized (and followed by self-proclaimed "forward thinking" GMs) since at least 2003. But here are the number of trips to the disabled list by just starting pitchers since 2000, including thus far in 2012.

2000 – 103
2001 – 87
2002 – 94
2003 – 87
2004 – 86
2005 – 79
2006 – 98
2007 – 118
2008 – 106
2009 – 111
2010 – 88
2011 – 93
2012 – 82

That all seems completely random to me. Pitchers get hurt, boys. There's nothing you can do except deal with it.