Evaluating Daniel Ponce de Leon, 2020 Rotation Option

The Cardinals have a lot of well-documented questions to answer in the rotation for 2019. As of today, there are two open slots, previously occupied by Michael Wacha and Adam Wainwright. Per Tuesday’s press conference, the Cardinals appear to be working on a reunion with Wainwright. Assuming the two sides reach agreement, that fills one requirement. The team has multiple options for the final spot in the rotation, but they have a pretty good solution already on the roster.

Plan A is almost certainly the return of Carlos Martinez to the rotation. It makes the most sense, it’s what Martinez wants, and it’s what the team wants. If healthy enough to start, he offers the best combination of reliability and upside. Failing that, plan B could take them to a free agent market that’s deep in options. It wouldn’t be surprising to see one or two of those options reach mid-March without a contract and receive a one-year pillow deal, particularly after what happened to Dallas Keuchel and Craig Kimbrel last off-season. Once all of that settles, if Martinez ends up back in the bullpen and the free agent options go elsewhere, chaos happens in the Cardinal rotation. An open competition would happen between Austin Gomber, Genesis Cabrera, Ryan Helsley, Jake Woodford, Alex Reyes (disregarding the obvious health concerns), and Daniel Ponce de Leon. It’s that last option, Ponce de Leon, I want to discuss today.

This all started when I was rifling through the effectiveness of the individual pitches for each Cardinal relative to the league. A few weeks ago when I looked at the free agent market, I mentioned that, ideally, a pitcher should miss bats and limit damage. In that article, I used swinging strike percentage and barrels per balls in play. When looking at individual pitches, I had shifted to whiff percentage (swings and misses divided by swings) and expected weighted on-base percentage on contact, against each individual pitch. It’s the same general concept as before- make hitters swing and miss, don’t allow loud contact- zeroed in on individual pitches.

My final step was to put both metrics on a league-relative scale, much like OPS+. Here’s how Ponce de Leon’s pitches fared this year, with 100 as average:

Four-Seam fastball

Whiff+: 129.46, xwoBACON+: 120.77

Cutter

Whiff+: 74.23, xwoBACON+: 102.82

Curveball

Whiff+: 72.75, xwoBACON+: 180.20

Changeup

Whiff+: 113.41, xwoBACON+: 120.49

His four-seamer and his changeup were both upper quintile in the league in 2019 if we take the harmonic mean of those two numbers. In fact, his four-seamer was 94th percentile, one of the most effective in the league. While his curveball didn’t amass many swings and misses, it was 94th percentile in limiting damage on contact. Using the harmonic mean, it was a respectable 64th percentile overall. Finally, his cutter was fairly ineffective, falling in the lower third percentile. Technically, Statcast labels it a cutter, though it may be a slider or even the rare slutter. You be the judge:

By the way, his fastball racked up almost as many swings and misses in the top of the strike zone as Jack Flaherty (42 for Flaherty, 33 for Ponce de Leon) in a fraction of the innings. If you want to know how a pitcher can throw his four-seamer 70% of the time as Ponce de Leon did and still be effective, this is how:

It’s probably ambitious to say it’s an elite pitch, but there’s more than enough skill in his four-seamer to carry Ponce de Leon to a lot of success.

When you put all of the pieces of his repertoire together, you end up with a pitcher who carried the following percentile ranks in 2019 (min: 200 batters faced):

His ability to limit hard contact this year bordered on elite, and his xwoBA on contact was tremendous. His barrel percentage allowed was even better than Flaherty, which is quite a measuring stick. His overall whiff percentage, non pitch-specific, was good enough to register in the top half of the league.

You can’t talk about the good with Ponce de Leon without also addressing the bad. His walk percentage was a dreadful 12.8%, 46th worst out of 457 pitchers with at least 30 innings. That lack of command has bedeviled him in both AAA and St. Louis. VEB writer emeritus Joe Schwarz frequently points to his inconsistent mechanics as a source for this issue.

Ponce de Leon’s percentage of pitches in the zone is bottom quartile in the league, as is his percentage of first strikes. His xwOBA when ahead in the count was a miniscule .157, one of the very best in the league. To state the obvious, he should get ahead of hitters more often.

If nothing else changes, Ponce de Leon has earned a full-season shot as a spot starter and multiple inning reliever similar to what John Gant provided for most of 2019. Particularly out of the bullpen, he can limit his approach to his two or three most effective pitches- the four-seamer, changeup, and curveball. Strictly in that role, he’s a perfect candidate to rip through an opposing team’s lineup one time in the middle innings.

Still, the building blocks of his repertoire are tantalizing. He feels like a pitcher who is one adjustment away from becoming a viable, middle of the rotation pitcher. Simply coming after hitters early in the count more often could do wonders, forcing hitters to chase later and decreasing Ponce de Leon’s walk percentage.

It’s hard to ignore his cutter lagging behind the other three pitches. Admittedly, he didn’t throw it much (13.4%), but it was his least effective offering. Either refining it into a completely different pitch or decreasing its usage seems like an obvious first step. Throwing fewer cutters and using a more aggressive first strike approach could be the key to unlocking the best version of Daniel Ponce de Leon. Even if he doesn’t do that, he has earned the right to stay off of the Memphis shuttle.