[心得] Aaron Crow, Starting Pitcher?
Aaron Crow, Starting Pitcher: Maybe Not The Best Idea
By Marc Normandin
With Jonathan Broxton on board, Aaron Crow is getting an audition for the
rotation. But should he?
Nov 29, 2011 - The Royals weren't very good at many things in 2011, but there
were two areas where they stood out: player development, and their bullpen.
Those were partially linked, thanks to the performances of rookie relievers
like Aaron Crow. While the ultimate fruits of their development labors are
yet to be seen, Kansas City made one move to help keep the 2012 bullpen as
good as the previous season's by signing Jonathan Broxton.
The downside to this move, though, is that there are only so many innings
available for relievers.(Even relievers coming in after Royals' starters.)
Because of this, Crow is getting a chance to move into the rotation in 2012.
In some ways he is an obvious fit: he posted an ERA of 2.76 last year, was
drafted as a starting pitcher in the first-round not once, but twice, and has
a nasty out pitch in his slider.
The presence of some positives doesn't mean it's a good idea, though. Crow
moved to the bullpen in 2011 for a reason, as he struggled throughout 2010 as
a 23-year-old in the minors. In his 163 frames, split between High- and
Double-A, Crow posted an ERA of 5.73, striking out just 6.8 per nine in
Double-A while showing control problems.
The Royals bumped him to the majors despite these issues, but placed him in
the bullpen. He excelled, striking out 9.4 batters per nine and posting an
ERA+ of 149. His walks were still a problem, but control isn't as much of an
issue for relievers as for starters. Nate Silver wrote about this back in
2006, when it wasn't clear just yet whether Jonathan Papelbon's future was as
a starter or reliever:
Walk rate--command--is strongly associated with the consistency of a
pitcher's mechanics. Pitchers who have difficulty maintaining the same
release point from inning to inning, or have trouble keeping their focus, are
prone to bouts of wildness. Turning such a pitcher into a reliever can
minimize this disadvantage, as he is less prone to fatigue, and may be able
to get away with using just one or two pitches.
Crow did this very thing, focusing almost entirely on his fastball and slider
in 2011. He used his mid-90s heater 54 percent of the time, and his slider
one-third of the time. That slider induced whiffs 26 percent of the time it
was thrown -- nearly double the effectiveness of a league-average slider.
Because he was able to focus more on his two best pitches, it didn't matter
as much that he had a difficult time throwing strikes overall -- Crow threw
every one of his pitches for strikes less often than your average hurler.
As a starter, he will need to expand his repertoire, utilizing his
rarely-seen curveball in order to mix things up. It doesn't miss a ton of
bats, and he has a difficult time throwing it for strikes; there is trouble
in that pitch's future.
Silver also discussed what you can expect from a pitcher moving from starting
to relief:
...the typical pitcher will have an ERA about 25% higher when pitching in a
starting role than when pitching in relief. That is, if you take a given
reliever with a 3.00 ERA, your best guess, all else being equal, is that his
ERA as a starter would be 3.75.
Does that mean that the average starting pitcher has an ERA 25% higher than
the average relief pitcher? No, it does not. Over the past decade or so, ERAs
of starting pitchers have run about only about 7% higher than relief pitcher
ERAs.
Why the disconnect? The simple answer is that starters, as a group, are
better pitchers than relievers. Starting pitchers, after all, are throwing
the bulk of your innings.
Crow had a 2.76 ERA, so that 25 percent jump would put him at 3.45 as a
starter. But that's not quite how it works, as in Silver's example, he is
talking about your average climb in ERA. Things could be much worse,
depending on the pitcher. Whether Crow was actually that good as a reliever
is also up for debate, given his 4.11 FIP. Add 25 percent to that figure
rather than his actual ERA, and Crow is expected to be somewhere over 5.00 as
a starter. That's a huge (and ugly) difference, and it's not even fully
taking into account what happens if his command and control don't improve, or
his curveball fails to develop as needed.
Tom Tango's "Rule of 17" is another solid guide for these conversions: K/PA
is up 17 percent as a reliever, BABIP is down 17 points, and home run rate is
down 17 as well. Viewed through that lens, Crow's 2011 stats would be at
about 7.8 strikeouts per nine, 1.4 homers per nine, and a BABIP of roughly
.313. Since walk rate remains a problem -- and is expected to remain flat
moving from relief to starting -- those homers would likely be for extra runs
more often than not.
The Royals have nothing to lose here, as their rotation is terrible with or
without Crow, but at first glance this seems like a temporary move given his
pitches and problems. When Crow throws in the spring, be on the lookout for
his curveball -- he's going to need it to work for this experiment to succeed
in the long-term.
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 219.81.163.35
Royals 近期熱門文章
PTT體育區 即時熱門文章
