Toolshed Stats: Prospect BABIP on mound

In addition to our weekly Toolshed column, every Tuesday during the first half of the offseason our new Toolshed Stats series will use advanced statistics such as ISO, FIP, Spd and park factors to better understand prospect performance during the 2016 Minor League season.

Two weeks ago, Toolshed Stats took on batting average on balls in play (BABIP) in relation to position players ranked among MLB.com's top 100 prospects. In the interest of "Gotta hear both sides" on the day after Election Day, it's the pitchers' turn to have their 2016 seasons considered through the same prism.

First, a quick refresher on BABIP. Its formula works as follows:

BABIP = (H-HR) / (AB-K-HR+SF)

The stat is fairly explanatory through its name alone, but it's important to note that it's a stat that primarily tells us more about other numbers, such as batting average or, in this case, ERA. When it comes to pitchers specifically, they can't control what happens to a ball as much as their hitting counterparts, and in that way, we're more inclined to look at high or low BABIPs as a function of good or bad defense or luck. (Keep in mind: an average BABIP is generally considered to be around .300.) They can control it in some ways though by forcing a lot of weak contact or being a primarily flyball pitcher, which tend to be easier to catch for defenses than a higher rate of groundballs.

But let's get one thing straight -- don't confuse a high BABIP for a bad pitcher. Noah Syndergaard (.334) and Jose Fernandez (.332) both finished among the top five highest BABIPs for Major League pitchers and yet both finished with ERAs below 3.00. What those high marks make us wonder is perhaps how much better those two could have looked had their BABIP normalized (particularly Syndergaard, who saw his BABIP skyrocket from .279 to .334 from 2015 to 2016).

With the table set, let's begin with the top-100 pitching prospects who suffered the high BABIPs this past season. You can also peruse the table of all top-100 pitching prospects and their BABIPs here.

Before we get going, let's note that there were four top-100 pitchers who actually posted higher BABIPs than the ones posted here, but none of the four -- Riley Pint (.390), Forrest Whitley (.388), Matt Manning (.379), Brady Aiken (.366) -- met our innings minimum (not a surprise considering the first three were 2016 Draft picks). If anything, that's a good reminder that BABIP can be noisy over small samples.

Among those who did meet the criteria, Alex Reyes sits atop the table by a healthy margin. Again some of that could be noise, since he was held back from a full season in the Minors by a suspension for marijuana use at the beginning of 2016 and a Major League callup in August.

A high BABIP, however, is not a new development for the Cardinals' top prospect. He posted a .371 BABIP over 63 2/3 innings at Class A Advanced Palm Beach in 2015, and over his four seasons in the Minors, his career BABIP allowed is .334. Why is that? For one, Reyes is typically a tough pitcher to homer off. He owns a career 0.4 HR/9, and even when that number spiked to 0.8 during his time at Triple-A Memphis, it was still below the 0.9 HR/9 average in the Pacific Coast League in 2016. In other words, a lot of batted balls stayed in the yard, even if they were hard-hit. Add in that the PCL already averages the most hits per nine innings (9.4) of any full-season Minor League circuit, and it's not hard to see that Reyes was in an environment that can lead to high BABIPs for low-homer pitchers. (It gets even more interesting when you note that his .220 average-against at home in seven starts at Memphis was significanly lower than his .285 average-against in seven road starts in hitter's havens like Colorado Springs, Albuquerque and Las Vegas.)

On the other hand, there might not have been much defense played behind the 22-year-old right-hander. As we noted in the FIP column, the gap between his 4.96 ERA and his 3.72 FIP was the largest among top-100 prospects this season. With typical defensive support, Reyes' season with Memphis looks a lot rosier. With 12.8 K/9, the only thing in the way of Reyes' success may not have been batted balls at all but his above-average 4.4 BB/9. Perhaps it should have come no surprise, then, that Reyes' Major League ERA (1.57), FIP (2.67) and BABIP (.283) were much better than his Minor League numbers. Part of that had to do with the Cardinals using of the righty out of the bullpen for seven of his 12 appearances. So, we shouldn't have been discouraged by Reyes' rough traditional numbers nor should we be surprised that he acclimated quickly to the game's highest level. He'll enter Spring Training as a member of the St. Louis rotation, and it'll be interesting to see if his trend of high BABIPs continues or if his 2016 Major League results were just the starting blocks of his new normal.

Moving quickly through the other four in the list, Espinoza had high BABIPs at both Greenville (.343) and Fort Wayne (.363) in a first full season in which he posted a 4.49 ERA and .276 average-against. Espinoza has a slight tilt toward being a groundball pitcher, but with his impressive stuff, you'd expect his BABIP to normalize in years to come. There was never a reason to panic about the 18-year-old, but this truly demonstrates that.

Holmes' .316 BABIP at Class A Advanced Rancho Cucamonga before his trade from the Dodgers to the A's was on the high side but nothing that would have registered in this column. His .408 BABIP at Stockton, however, is what helped him get here. Again, it may be noise, but Holmes ranked seventh in the California League with a 4.09 FIP compared to his 4.63 ERA.

We always knew that Hader was a victim of the Pacific Coast League, but BABIP might be the last shred of evidence we need. The 22-year-old left-hander had never posted a BABIP higher than .301 at any level before moving up to Triple-A Colorado Springs, where it jumped to .345. He'll need to cut down on the walks, for sure, with a 4.7 BB/9 at the Minors' highest level, but between the BABIP and a career-low 63.2 percent left-on-base percentage, his 5.22 ERA isn't as much about his poor pitching performance as one would expect. 

With 50.6 percent of his batted balls against going on the ground this season at Class A Advanced Potomac, Fedde was the perfect high-BABIP candidate. His BABIPs in first two Minor League seasons: .314 and .327.

Let's start by praising Lousiville's defense. Two Bats pitchers appear above, and it might not be a coincidence. Garrett was a decent groundball pitcher in 2016 with 50 percent of his batted balls coming on the ground -- a number that'd make you expect a higher BABIP. That wasn't the case with Stephenson (41.4 percent), but his 4.41 ERA was somehow still better than his 4.65 FIP indicated it could have been. If either pitcher appeared here alone, we might think there was some luck at play. Together it may mean something.

Mendez was essentially the mirror image of Holmes in that his .285 BABIP-against through July 30 (mostly at Class A Advanced High Desert and Double-A Frisco) wouldn't have been all that notable. However, a .132 BABIP in August at Triple-A Round Rock season average the .247 seen above. Nothing in the 21-year-old left-hander's past nor in his batted-ball data points to an adeptness to regularly force such low BABIPs going forward, so it'll be on Mendez to prove that his 2016 breakout across three levels and into the Majors was sustainable.

Gonsalves continued his trend of low BABIPs at Class A Advanced Fort Myers (.249) and Double-A Chattanooga (.255), beating out even his career BABIP against of .271 at both locations. While the 22-year-old left-hander doesn't have any pitches that grade out better than slightly above-average, he's shown positive results at almost every stop with a career 2.13 ERA and 9.7 K/9 over four seasons. His lack of stellar stuff might get exposed at higher levels, but even at Double-A Chattanooga, Gonsalves posted a 1.82 ERA, 2.76 FIP and 10.8 K/9 over 74 1/3 innings.

De Leon went the flyball route to a low BABIP during his time at Triple-A Oklahoma City. In fact, the 24-year-old went so far against the grain that he actually allowed more flyballs (37.1 percent) than groundballs (36.7 percent). For reference, pitchers gave up an average of 44.7 percent groundballs and 34.6 percent flyballs in the Majors during the 2016 regular season. His 15.7 line drive percentage -- i.e. balls that are also generally tougher for defenses to catch -- was also well below-average, making for a good low BABIP recipe. He'll need to make those numbers translate to the Majors -- not to mention do a better job of keeping the ball in the yard (he allowed five homers in 17 Major League innings) -- if he's going to do a better job of sticking in the Los Angeles rotation in 2017.