Red Sox: Diving into Rick Porcello’s home run problem

BOSTON, MA - AUGUST 15: Rick Porcello
BOSTON, MA - AUGUST 15: Rick Porcello /

Rick Porcello has given up far more home runs this year than he did in 2016 with the Red Sox. A lack of deception could explain the unpleasant change.

All season long, Boston Red Sox starter Rick Porcello has had a problem. The reigning American League Cy Young Award winner has looked nothing like the 22-game winner of a year ago at any point this season.

Porcello’s ERA sits at 4.67, up from 3.15 last season. Renaissance campaigns from Doug Fister and Drew Pomeranz may, during the regular season, mitigate the damage an ineffective Porcello could have otherwise done. However, the Red Sox will need Pretty Ricky at his best in the playoffs, either as a starter or coming out of the bullpen.

Through the first nine days of September, there’s no evidence that they should expect to get it.

Numbers Game

Porcello’s issues stem largely from the fact that his home run rate rose dramatically this season. Across a full 2016 campaign, Porcello allowed 23 home runs at a clip of 0.93 per nine innings. This season, opponents have already collected 35 long balls against the 28-year-old. His HR/9 rate currently sits at an alarming 1.74. That number easily represents a career-high.

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It’s no coincidence that some of Porcello’s other peripheral stats also look very different this season. His strikeout-to-walk ratio has dropped from a healthy 5.91 in 2016 to a meager 4.18 this year. While his strikeout rate has actually improved, his walk rate is up to 1.94; last season, it sat at 1.29.

Upon closer inspection, it becomes clear that Porcello simply hasn’t been able to fool batters as often this season. His O-Swing%, the percentage of pitches thrown outside of the strike zone that hitters swing at, dropped from 31.6% last year to 30.8% this year. More dramatically, his Z-Swing%, the percentage of pitches thrown inside the strike zone that hitters swing at, has risen from 65.1% in 2016 to 69.5% in 2017.

This has led, predictably, to significant drop-offs in the effectiveness of all of his offerings. Porcello has never been the type of pitcher who can blow batters away. He’s always relied on above-average control and deception. Without that, his arsenal is rather ordinary.

Diving Deeper

Let’s compare the values of each of his pitches from last season to this season. Pitch value measures the number of runs saved by each type of pitch used. A pitch value of 0.0 is average; a positive figure is above average, while a negative figure is below average. Porcello’s wFB figure, which measures the total number of runs saved by his fastball, was a strong 13.0 in 2016. In 2017, it’s flipped completely and currently sits at -13.0. His other pitches have seen similar drops. His wSL (slider value) dropped from 8.0 to 2.8; his wCB (curveball value) fell from -1.1 to -3.4; his wCH (change-up value) is down from 10.0 to -5.0.

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While in some cases a drop in pitch value could correlate to a change in usage rate, that is not the case here. Porcello’s pitch usage rates are largely the same this season as they were last season.

In addition, when accounting for different usage rates between each of his pitches, we still see a decline in value from 2016. Porcello’s wFB/C number, which measures the number of runs saved by that type of pitch per 100 thrown, finished at 0.62 in 2016. In 2017, it’s down to -0.76. His wSL/C sat at 1.90 in 2016, but is now at 0.54. His wCB/C has gone from -0.23 to -0.72, and his wCH/C slipped from 2.42 to -1.81.

Whether due to some undisclosed injury or to an undiagnosed mechanical flaw, hitters are seeing the ball better out of Porcello’s hand this year than they did in 2016. He somehow lost a good deal of his deception.

Next: Red Sox September Standings Watch

On the bright side, there’s good reason to believe he’ll be able to find it again. His 2015 numbers in many of the above-examined categories look more like his 2017 numbers than his figures from last season. He turned things around once already in his Red Sox tenure; he can probably do it again. Unfortunately, Boston needs him at his best now; if they have to wait for 2018, it could seriously impact their 2017 title dreams.