Hernandez’s Change Needs Change | The Process Report

Hernandez’s Change Needs Change

The signing of Roberto Hernandez may have been a surprise at the time, given the Rays’ pitching depth, but Jeff Niemann’s fragility and the team’s desire to nurture their young starters paved Hernandez’s path to the opening-day rotation. Early in the season Hernandez generated as many whiffs as Matt Moore, suggesting perhaps the results would finally match his stuff—a long-time discrepancy that Tommy Rancel fingered as a potential sequencing problem:

Since 2007, batters have swung and missed on 25 percent of swings against Hernandez’s slider and 30 percent of hacks against his changeup, according to brooksbaseball.net. Pitchers with similar whiff rates over the last few seasons include Madison Bumgardner,Matt Cain, and Johnny Cueto (sliders), along with Jake PeavyCliff Lee, and John Danks(changeups). This is not to say Hernandez is as good as those pitchers, but to show that his secondary stuff is worthy of primary usage.

Hernandez’s changeup missed bats 33 percent of the time in April. But in the time since batters have seemingly adjusted to Hernandez’s new gameplan, and his strikeout and whiff rates have declined in each subsequent month:

graph

It’s not just an adjustment on the opposition’s part, however. But a failure on Hernandez’s part to execute. In April, when the changeup was missing bats at a high clip, he was religiously placing the pitch arm-side low; if he missed he missed down or off the plate.  In July Hernandez has attempted to expand his changeup usage to his glove-side. Yet, as the heat maps below show, he’s often thrown changeups  in places where he’d rather avoid:

strike-zone (16)

strike-zone (17)

The location of the pitches has led batters to swing more but whiff less, costing the pitch its effectiveness. If Hernandez wants to get back to his surprising ways he’ll need to begin location arguably his best pitch more often.

Stats and visualizations courtesy of ESPN Stats & Info



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