Zack Greinke Reverses FIP-ERA Gap But Loses Strikeouts

Zack Greinke had another excellent season in 2013, placing 14th in the end-of-season starting pitcher rankings and sporting the league’s fifth-best ERA at 2.63.

But how did Greinke rank outside the top-ten despite a top-five mark in ERA, a top-10 mark in wins (15) and a top-15 mark in WHIP (1.11)? It’s because for the second straight year, Greinke’s strikeout rate saw a dramatic drop, even though his swinging strike rate rebounded to double-digit levels.

Should we be concerned that Greinke struck out just 20.6 percent of batters he faced, and is there anything else concerning in his profile?

Let’s step back and look at the positives, first. Greinke still doesn’t walk anybody, he coaxes an above-average amount of ground balls and he pitches his home games in Chavez Ravine, at worst a neutral park for homeruns. Those things are unlikely to change, and as long as Greinke takes the mound consistently, they limit his downside pretty significantly.

But the strikeouts are a flag, falling from 10.5 per nine-innings to 8.5 and now 7.5, with the per-plate appearance mark falling from 28.1 percent to 23 percent to 20.6 percent.

2012’s drop can be explained in part by a drop in swinging strike rate from 10.6 percent to 8.5 percent, a drop that was accompanied by a decrease in outside-swing rate and overall swing rate and an uptick in batter contact rate. In short, hitters fared better against Greinke in 2012 in discipline and contact terms.

But in 2013, all of these trends reversed back to, or even past, their 2011 marks. The outside-swing rate hit a career-best 31.5 percent and the overall swing rate peaked at 46.9 percent. As such, the swinging strike rate jumped back to 10.4 percent, just off his career high.

However, swinging strike rates, while useful for predicting strikeouts alongside velocity, aren’t everything. Strikes looking and fouled strikes added to the mix have proven more predictive and highlight an issue beneath Greinke’s strikeout decline – while the swinging strikes came back up, the rate at which he got looking strikes declined dramatically, from years at 30 percent and 32 percent to a career-low 25 percent.

Using Podhorzer’s strikeout formula linked above, perhaps this decline shouldn’t have been surprising:

Essentially, batters have made the conscious decision to swing at more Greinke offerings and, while they make below-average contact, they’re giving away fewer of his above-average number of pitches thrown in the zone. It seems Greinke could stand to live on the outside a bit more often, but whether this would hurt his other-worldly ability to get whiffs in the zone is unclear.

Of course, some of this strikeout decline may also be due to a decrease in deception thanks to Greinke’s trading in of a heavy slider usage for a mix of sliders and cutters:

Greinke first introduced the cutter in 2012, slashing his slider usage from nearly 20 percent to the 12-13 percent range. The cutter has made up the difference and has been a much less effective pitch. In fact, the non-PITCHf/x pitch classifications basically showed Greinke as having abandoned the slider for a cutter entirely.

Meanwhile, the whiff rate on what’s classified as his slider fell from 50 percent to 33 percent this season, thanks to a precipitous decline in both horizontal and vertical movement (per Brooks Baseball, linked earlier). The slider is still a better pitch than the cutter but it was far less of a weapon in 2013.

The drop may come as a response to injury concerns after years of near-20 percent slider usage, which is fine, but it puts additional pressure on Greinke’s other pitches and ability to keep hitters guessing.

And if you’re thinking the strikeout decline is an overall positive considering Greinke’s ERA has fallen with his strikeouts the past three seasons, think again. His FIP and xFIP have slowly ticked upward, and the ERA flip was largely due to Greinke reversing his trend of high-BABIPs with men on base. You can buy into a high strand rate (80.8 percent) for an elite arm, but a .249 BABIP with runners on following three seasons of that mark being north of .300 is the root of the change.

Whether Greinke repeats as a top-20 pitcher depends largely on his health and whether or not he employs the slider, two factors that may be somewhat related. The fastball, change and curve all remain effective pitches but the cutter needs to catch up or be swapped back out for the slider. He’ll still be very good, but he may not be an elite fantasy option without finding a way to get those strikeouts back.

On a side note, if you ever find a league that counts pitcher hitting stats, Greinke immediately becomes a top option. He slashed .328/.409/.379 and had the highest wRC+ (132) for any pitcher since 2003.