Inside McCarthy's transformation with the Yankees

Where would the Yankees be without McCarthy in the rotation? (Photo: Jim McIsaac/Getty Images) Brandon McCarthy arrived in the Bronx with a 5.01 ERA but somehow has emerged as the de facto ace of the Yankees staff over the last six weeks. He has a remarkable 2.30 ERA and four wins in seven starts – numbers that even Brian Cashman could not have imagined when he traded for the sinkerballer at the beginning of July.

Let's take a deeper look at some of the adjustments by McCarthy that have made him into one of the most effective pitchers in the AL during the past month and a half. Hint: It's more than just slimming pinstripes that have helped him.

It is high, it is is not gone The most fundamental difference in McCarthy's performance since coming east is his ability to limit the longball. He gave up 15 homers in 109 2/3 innings as a Diamondback, but only three home runs in 43 innings as a Yankee.

Some of that difference is likely the result of the expected “regression to the mean” effect. His homer-to-flyball ratio with Arizona (21%) was among the highest in the majors in the first three months of the season, and has been cut in half since coming to New York (10%).

But it's not only about luck. McCarthy has reduced the amount of hard contact he's allowed and batters are having a much more difficult time squaring up on his pitches.

In Arizona, he allowed a hard-hit ball in 18 percent of opponents' at-bats, the 11th-highest mark among all pitchers through July 3. His hard-hit rate as a Yankee is 13.6 percent, which is slightly better than the major-league average (14.6%).

His flyball distance allowed has also dropped 20 feet (from 286 to 266), another indication that his stuff has become more effective since joining the junior circuit.

This has led to a 100-point drop in opponents' slugging percentage and a significant decrease in the number of damaging hits allowed by McCarthy.

Source: ESPN Stats & Information

An obvious reason for his newfound ability to limit extra-base hits is an improvement in his location. He is leaving fewer pitches over the vertical middle-third of the plate, and serving up fewer meatballs for batters to crush over the fences.

Back to the cutter Much of the analysis surrounding his transformation in pinstripes has focused on the shift in McCarthy's pitch repertoire, specifically the increased usage of his cutter. But exactly how has this change in approach made him a better pitcher in New York?

The cutter hasn't been a dominant out-pitch – he is actually going to it less often in two-strike counts as a Yankee – and it isn't generating more grounders or whiffs. He is also getting similar results when batters put the pitch in play: a .233 batting average allowed as a Yankee vs a .231 batting average allowed as a Diamondback.

Rather, the increased usage of his cutter has made McCarthy a less predictable pitcher and kept hitters off-balance, especially when he pairs the pitch with his sinker.

Since joining the Yankees, McCarthy has ended an at-bat with a sinker 97 times. Seventeen of those 97 sinkers were preceded by a cutter, and in those “cutter-sinker” at-bats, opponents are 2-for-17 (.118) with five strikeouts.

This doesn't necessarily mean that he should always use that cutter-sinker pitch sequence – the more predictable he is, the worse results he'll likely get.

But the fact that he is more comfortable throwing his cutter in any count gives hitters something else to think about when facing McCarthy, and has made him a better pitcher with the Yankees.