Mets' John Mayberry has struggled as a pinch hitter this year

Pinch hitting is a difficult way to make a living. As Amazin' Avenue's Aaron Yorke noted over the winter after the Mets signed John Mayberry, "pinch-hitting performance can vary wildly from year to year, even when highly experienced bench bats are involved."

In 2014, John Mayberry was the best pinch hitter in baseball. Overall, he hit just .212/.310/.425, but as a pinch hitter he hit .400/.438/.933 with eight extra-base hits in just 32 plate appearances. That production has not carried over to the first third of 2015, as Mayberry has struggled mightily. Entering Tuesday's game against the Toronto Blue Jays, Mayberry had 22 plate appearances as a pinch hitter, and he was batting just .118/.318/.118 without an extra-base hit. A slight regression might have been expected, as Mayberry had.400 BABIP as a pinch hitter in 2014. In 2015, however, his BABP as a pinch-hitter has plummeted to .167.

Overall, Mayberry has hit .209/.284/.418 with a 98 wRC+. That OPS, though, has been enhanced significantly in the past week. If you remove Mayberry's 4-for-5 performance at Arizona on June 4 and last Friday's 2-for-2 against Atlanta, he would be hitting just .133/.212/.233. As when trying to analyze an everyday player during the season's first few weeks, one or two good or bad performances can cause the numbers to fluctuate wildly. For example, on Friday against Atlanta, Mayberry raised his OPS by 100 points in just one game.

Success against changeups

So, apart from two of the first sixty-two games, just why are Mayberry's number down so substantially a year after he was the game's best pinch hitter? As you will see below, pitchers have not approached Mayberry much differently, nor has his production changed against the three pitches he sees with the greatest frequency:

Four-Seam Fastball:

	Frequency of Pitches Seen	AVG	SLG
2014	39.3%	.255	.546
2015	32.0%	.250	.625

Sinker:

	Frequency of Pitches Seen	AVG	SLG
2014	21.3%	.161	.323
2015	27.9%	.188	.563

Slider:

Pitch	Frequency of Pitches Seen	AVG	SLG
2014:	14.1%	.200	.300
2015	16.5%	.167	.250

While the frequency and production against four-seamers, sinkers, and sliders has not varied greatly, Mayberry's production against changeups has dropped significantly:

	Frequency of Pitches Seen	AVG	SLG	HR
2014	8.9%	.313	.750	2
2015	8.1%	.250	.375	0

A drop in production, no matter how substantial, against the pitch Mayberry sees the fifth most often might not seem like a big deal. However, in 2014, despite seeing changeups just 8.9% of the time, nearly one-fifth (19.4%) of his total bases came off changeups. In 2015, he is seeing changeups with the same frequency, but his total bases against the pitch have been cut almost in half (10.7% of total bases).

Success on low-inside pitches

And while Mayberry's strikeout rate in 2015 (24.3%) has increased only slightly from 2014 (23.4%), his whiff rate on pitches in the bottom half and inside corner of the strike zone has increased dramatically:

And 2015:

As you can see below, it's on the bottom and inside corner of the strike zone that Mayberry did his most damage in 2014:

Mayberry did show flashes last weekend in Arizona and Friday night against Atlanta. Perhaps he is heating up, and his BABIP should rise, but the extra-base hits as a pinch hitter have been absent in 2015. Mayberry is whiffing more frequently against pitches he hit for power in 2014, and the power against changeups has disappeared. Before Friday's game, Mayberry had been worth just 0.1 fWAR though more than a third of the season.

Pinch hitting is not easy, but that's primarily what Mayberry is here for and he definitely needs to to a better job than he has so far in 2015.