In a tale of two haves, Mike Pelfrey’s 2010 season has taken a sharp turn for the worse since June 13.  Entering the June 13th Sunday matinee game against the lousy Baltimore Orioles, who currently rank 27th in the majors in runs scored, Pelfrey has seen his ERA steadily rise with each outing, with the exception of his recent July 24th outing against the at time struggling Los Angles Dodgers when Pelfrey managed to drop his ERA a miniscule 0.01.  After coming off a nine inning, one hit, and one earned run performance against the San Diego Padres at home, a game Pelfrey received a no decision for because the game went extra innings, Pelfrey saw his ERA stand at a sparkling 2.23.  However, Pelfrey’s good fortunes came crashing down as his ERA has progressively risen since his nine starts after that, with the aforementioned exception, and it currently peaks at an unwanted 4.10.  In this piece, I’m trying to dissect the numbers and see what Pelfrey’s sudden collapse can be attributed to.


            In Pelfrey’s starts pre-June13th (which will be referred to as the first half), he threw his 4-seam fastball 45.3% of the time, averaging 91.8 velocity while doing so.  The next most used pitch by Pelfrey was his 2-seam fastball, which can be interchangeable with Pelfrey’s sinker, which he threw 21.8% of the time.  The third most used pitch was the changeup, Pelfrey’s preferred off-speed pitch in which he averaged 84.1 velocity on.  The fourth used pitch thrown 7.3% of the time was Pelfrey’s slider, followed by a cutter thrown 5.8% of the time, and lastly his newly found split-finger thrown a measly 0.7% of the time.  In the second half starts (the June 13th game and later) Pelfrey’s most widely used pitch was his 2-seamer/sinker, which he threw for 35.9% of the time.  His second most used pitch was his, 4-seamer; however its usage has dramatically decreased and has only been thrown 32.1% of the time, a 13.2% loss from the first half.  However, the increased usage of the sinker and decreased usage of the 4-seamer is most likely connected to the fact Pelfrey was trying to induce groundballs for a potential double play as he’s been putting more runners on the base paths.  True to the first half, the third most used pitch and favored off-speed pitch was the change-up, which was thrown 12.9% of the time.  Gaining a healthy increase in usage was the split finger, which ranked fourth among pitches thrown at a 7.3% rate, netting a 6.6% gain.  The last two pitches were the slider and cutter, thrown 6.5% and 5.2% of the time, respectively.   For the record, the average fastball velocity in the second half was 92.2, a .04 increase from the previous mark proving velocity is a non-factor.


            Next, it’s important to look at the effectiveness of each pitch.  The 4-seamer’s average whiff rate of 6.0% in the first half compared to a 5.2% in the second.  The sinker averaged a whiff of 7.2% in the first half against a decreased 4.75% after the Padre game.  The changeup plummeted from a 12.9% rate all the way down to 6.9%.  The slider whiff rate actually rose from a 3.1% to a more modest 7.8%.  The newly acquired split finger had a respectable 7.0% rate when it became used in the second half.  Lastly, the rarely used cutter graded high in both halves posting whiff rates of 11.7% and 9.8%.  Looking even deeper, we see that Pelfrey has much better control on his fastball and sinker which enables him to pound the strike zone – posting strikes on 62% or higher for both the 4-seamer and sinker in both halves.  However, when Pelfrey throws the change, he loses some control and throws around 57% for strikes.  Another factor that should be taken into consideration is the fact that Pelfrey is hanging his off-speed stuff and making his pitches more hittable.  In the first half, Pelfrey had in play percentages of 26.7%, 15.5%, and 18.2% on the changeup, slider and cutter.  In the second half, he posted in play percentages of 21.8%, 17.6%, 12.2%, and 22.8% on his changeup, slider, cutter, and split finger.   The percentages for the established pitches remain relatively stable, but the newborn split finger posted an unfriendly 22.8% for an off-speed pitch. 


            Furthermore, in the month of April, Pelfrey posted an absurdly lucky 93.6 LOB% (left-on-base percentage) and a .249 BABIP (batting average on balls in play), two numbers that represent luck and that will inevitably revert back to career norms over an adequate sample size.  As kind as April was to Pelfrey, July was just as harsh.  In the past month, Pelfrey’s luck has apparently vanished indicated by his 58.6 LOB% and .459 BABIP. In addition, for the month of April Pelfrey posted a microscopic 0.69 ERA compared to his ugly 10.02 mark for July.  To the further add to the harm, Pelfrey’s solid line drive percents of 20.3, 20.7, and 20.5 during April, May, and June have jumped to 24.1% for July – so clearly Pelfrey has been making his stuff more hitter friendly allowing his opposition to make better contact.  However, the months of May and June profile Pelfrey’s realistic expectations as he posted a fair 75.3 LOB% in both months, with a .307 and .301 BABIP in May and June (league average on BABIP is around .300).  During those two months, Pelfrey also posted an ERA of 3.82 and 3.54, the type of consistency the Mets would love from their supposed number two starter.


            In conclusion when looking at all the data, Pelfrey’s recent ineffectiveness can be attributed to a couple of things.  First, Pelfrey has incorporated a new plan of attack for whatever reason since the Padre start: to throw more off-speed stuff.  More specifically, Pelfrey introduced his split finger and so far the results of the pitch have been disappointing.  To add on, with the increased use of the split-finger and the rather high in play rate, coupled with the visual test, it’s evident that Pelfrey is hanging the pitch at times.  Looking at the split-finger location chart, courtesy of the Pitch-FX tool, we can see Pelfrey is clearing leaving the pitch over the plate and isn’t pounding it towards the lower part of the strike zone.  Secondly, we can see that hitters have started to figure out Pelfrey’s stuff and that he’s leaving things over the plate.  Factor in the increased line drive rates and the decrease in fly ball rates over the season and it’s clear hitters are getting the barrel of the bat on the ball. The walk rates have actually improved over the season as he walked 8.81% of batters faced in the first half compared to 7.73% in the second half, so control can’t be an issue.  When putting it all together, Pelfrey’s been moving away from his heater and instead has reverted to throwing his off-speed stuff.  Pair that with some bad luck, hanging off-speed stuff, leaving things over the plate, and essentially making his arsenal more hittable, and Pelfrey has made his first half success a distant memory.  Going forward, Pelfrey will probably settle down with numbers similar to May and June as he certainly won’t consistently repeat his luck from April and should eventually figure things out from his July misfortunes.  For the sake of the Mets’ playoff chances, the organization is hoping he figures it out before his Wednesday outing against the division leading Atlanta Braves.

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