That essentially debunks the whole "Sanchez has matured" theory, right? Somewhat.
SIERA tells us a little more about Sanchez, because it adjusts for some of the flaws of FIP/xFIP. Here's where I think it's most applicable to Sanchez:
Allows for the fact that a low fly-ball rate (and therefore, a low HR rate) is less useful to pitchers who strike out a lot of batters (e.g. Johan Santana's FIP tends to be higher than his ERA because the former treats all HR the same, even though Santana’s skill set portends this bombs allowed will usually be solo shots).
From 2008-2010, Jonathan Sanchez's K/9 (9.40) ranked second in the majors only to Tim Lincecum. His GB% over that time period? 41.1% -- which is quite a bit below major-league average GB% (which hovers around 44%). So Sanchez is sort of in the same boat as Santana? Sort of.
Where he differs, significantly, is his extremely high walk rate. His BB/9 of 4.57 from 2008-2010 is the highest of any major-league starter over that span. This essentially separates Sanchez from Santana, as Sanchez allows fewer solo shots because of it.
Still, SIERA paints a better picture of Sanchez than FIP/xFIP:
And this picture, to a certain extent, happens to be consistent with the whole narrative. His development isn't nearly as drastic as the drop in ERA would indicate, but -- as far as SIERA is concerned -- it's there...steady and gradual improvement.
His strikeout rates would lend to the idea that Sanchez has the potential to develop into an ace, so is he -- slowly -- on this path? Probably not. And the walks kill him.
Sanchez is one of four expansion-era starters (min. 500 IP) to maintain a K/9 above 9 and a BB/9 above 4. How did these guys fair?
| Rk | Player | IP | From | To | Age | |||
|---|---|---|---|---|---|---|---|---|
| 1 | Rich Harden | 122 | 9.13 | 4.16 | 845.2 | 2003 | 2010 | 21-28 |
| 2 | Nolan Ryan | 112 | 9.55 | 4.67 | 5386.0 | 1966 | 1993 | 19-46 |
| 3 | Jonathan Sanchez | 101 | 9.44 | 4.60 | 612.1 | 2006 | 2011 | 23-28 |
| 4 | Oliver Perez | 91 | 9.12 | 5.08 | 1111.2 | 2002 | 2010 | 20-28 |
An interesting list, to say the least. But what does this tell us? Essentially, that it's uncommon for a pitcher to maintain such high K and BB rates. And not much else. So let's try to, slightly, expand the parameters and see what else we have here...pitchers who maintained K/9 above 8.5, and BB/9 above 3.5:
| Rk | Player | IP | From | To | Age | |||
|---|---|---|---|---|---|---|---|---|
| 1 | Rich Harden | 122 | 9.13 | 4.16 | 845.2 | 2003 | 2010 | 21-28 |
| 2 | Erik Bedard | 121 | 8.75 | 3.56 | 827.0 | 2002 | 2011 | 23-32 |
| 3 | Yovani Gallardo | 115 | 9.19 | 3.79 | 520.0 | 2007 | 2011 | 21-25 |
| 4 | Sam McDowell | 112 | 8.86 | 4.74 | 2492.1 | 1961 | 1975 | 18-32 |
| 5 | Nolan Ryan | 112 | 9.55 | 4.67 | 5386.0 | 1966 | 1993 | 19-46 |
| 6 | Scott Kazmir | 106 | 8.74 | 4.17 | 1022.0 | 2004 | 2011 | 20-27 |
| 7 | Jonathan Sanchez | 101 | 9.44 | 4.60 | 612.1 | 2006 | 2011 | 23-28 |
| 8 | Hideo Nomo | 98 | 8.73 | 4.13 | 1976.1 | 1995 | 2008 | 26-39 |
| 9 | Oliver Perez | 91 | 9.12 | 5.08 | 1111.2 | 2002 | 2010 | 20-28 |
Again, an interesting list. Here you have Nolan Ryan, one of the greatest pitchers of all time. You also have Rich Harden and Erik Bedard, a couple of guys who have had injury problems. Then you have Scott Kazmir and Oliver Perez, two pitchers who, as you probably know, have rapidly fallen off -- in their late 20s. Again, it's hard to learn much from this, as it's quite a small sample size. But this list doesn't really instill optimism about Sanchez's future.
Anyway, this much is quite obvious regarding Jonathan Sanchez: as long as he walks opposing hitters at absurdly-high clips, he won't be able to reach elite status as a starter; in fact, he'll probably begin to struggle to maintain status as an above-average starter -- as he'll need the high K rates to off-set his walks.
While Sanchez has showed some minor progression over the past few years, he's 28 years old, and it's likely that the Sanchez we see today isn't going to get much better. That said, the Sanchez we see today is undoubtedly a good pitcher, and that will -- in all likelihood -- remain the case over what are quite possibly Sanchez's final two years with the San Francisco Giants.
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