Mike Pelfrey will get the opening day nod in 2011.  In some ways, this has been a long time coming.  After the Mets drafted Mike with the 9th pick in the 2005 draft, Big Pelf was supposed to be an ace for a long time.And Mike has had his moments.  For most of 2008, he pitched very well, finishing with a 3.72 ERA and 13 wins.  That was followed, however, by a frustrating 2009 where he had an ERA above 5 and finished with a losing record.  For the first half of 2010, Mike appeared to have finally arrived, going 10-1 and generally dominating.  A poor July brought Mike back to earth, and he finished with overall numbers that were very similar to his 2008 (3.66 ERA with 15 wins).The prevailing wisdom in Met-world seems to be that if Mike can just “keep his head on straight” he will be the pitcher we saw in the first-half of 2010 and the second half of 2008.  Advanced pitching metrics, however, are more dubious.  For example, SIERA, which looks at what a pitcher’s ERA should be based on strikeout rate, ground ball rate adjusted for ball park and defense had Mike at 4.59 in 2010.  This suggests Mike is due for a pretty big step back in 2011.So, let’s look at what the major projection systems anticipate for Pelf in 2011:Baseball Prospectus:
WERAK/9BB/9
2011104.384.83.4
Marcel:
WERAK/9BB/9
2011124.005.653
Bill James:
WERAK/9BB/9
124.255.443.31
In short, each foresees a pretty major drop-off for Pelf.  Why?  The big reason is that his statistical improvement in 2010 seems to be based more on luck than anything else.  Let’s take a look at his peripheral stats in both 2009 and 2010 to illustrate:
K/9BB/9HR/9BABIPGB/FBLD%
20095.223.22.88.3121.7118.7
20104.993.00.53.3001.4920.2
Essentially, Mike lowered his ERA by more than a run, even though he struck out fewer batters per nine innings, generated fewer ground balls per fly ball and gave up more line drives.  Based on his batted ball data, Pelfrey’s BABIP should have gone up and he should have given up more home runs – instead, his BABIP went down 12 points and he gave up fewer home runs.  He also got much better at stranding runners on base, which most stats folks believe is due to luck.  The average velocity on his fastball even dropped from 92.6 mph to 92.You might be thinking, but the above doesn’t account for Mike’s new split-fingered fastball.  And indeed, Mike did start throwing a splitter in 2010.  He threw it 16.3% of the time and threw both his fastball and slider less.  If Mike’s splitter (and not luck) were at work, we’d expect Mike to generate more swinging strikes (SWStr%) and also more contact made with pitches thrown out of the strike down (O-Contact%).  The reason being that a splitter is effective when it causes batters to swing at a pitch that ducks out of the zone.  Think Mike Scott in the ’86 NLCS.  Alas, the splitter seems to have had no effect whatsoever.
SWStr%O-Contact%
20095.876.8
20106.076.7
And again, Mike didn’t get more ground balls or strike outs either.To sum up, there’s good reason to think that the projections for Pelf are right on for 2011.  He’s not a bad pitcher.  But he’s also not a true ace.  I’d figure on a 4.10 ERA with somewhere between 10 and 15 wins.  Unless he gets lucky.