RotoBaller embarks on a new series this year using Statcast to extrapolate, dig into, and commiserate over data to examine pitching performance. The weekly series will be dynamic as we fine-tune our findings and I enlighten myself on the information and tools at my disposal.

This week we'll focus on a popular batted-ball metric, Batting Average on Balls In Play (BABIP). Most fantasy players know BABIP is a critical statistic to understand when evaluating both hitters and pitchers. A player's BABIP (relative to his peers) is rooted in three main components: defense, luck and talent level. Since two of three pieces are out of players' control, BABIP can cause wide deviations between expected (FIP, xFIP) and reported performance (ERA). Fangraphs argues hitters need 800 and pitchers 2,000 balls in play (BIP) before they reach a steady-state. Either way, the league average BABIP is about .300 so we'll anchor to that figure.

Of course, no pitcher through three weeks has 2,000 balls in play so we're left to our biased devices. We'll look at starters with over 200 pitches, which equates to about 45-50 BIP. Fortunately, the small BIP sample should allow us to readily identify some pitchers that will ultimately improve or deteriorate as the season progresses.

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Bullish Signals

All stats as of April 17, 2018

Sonny Gray, New York Yankees (1-1. 6.92 ERA, 1.92 WHIP)

Sonny Gray started the season harmlessly enough, with two so-so starts before running in the Boston buzzsaw on April 12 (L, 3 IP, 6 ER, 7 H, 2 BB), leaving his headline numbers at the monstrosity they are today. Gray has the eighth highest BABIP out of 127 qualifying pitchers at .419. Unless every hitter he's facing is Ty Cobb (see: 1911), these figures should mercifully normalize.

To start, Gray's career BABIP is .279, lower than league average. His ERA is also running almost double the rate of his xFIP this season (3.79), so that's encouraging. His velocity and Hard% are stable year-on-year and the current 10.38 K/9 is the best pace in his six pro seasons. Another unfortunate development for Gray is a 61.5% LOB% that is bottom-15 for pitchers with at least 13 innings pitched. It's not all excuses though, Gray has had control issues (4.85 BB/9), compounding the BABIP problem and restricting his capacity to last deep into games. He also hasn't allowed a home run (not related to BABIP), which works in his favor.

Most drafters spent an early double-digit round pick on Gray so it's not advisable to panic and drop him immediately. I'd recommend rolling him out irrespective of the ugly start in belief that he'll get on track sooner than later. That starts this weekend at home against the Blue Jays.

Vince Velasquez, Philadelphia Phillies (1-1, 3.52 ERA, 1.37 WHIP)

I tried touting Vince Velasquez as a sleeper this preseason, but his current 16% ownership attests to my questionable influence and pitiful Twitter following. Here we are again, and after three starts, Velasquez has passable numbers. After getting bombed by Atlanta in his season debut (2.2 IP, 4 ER, 9 H, 2 BB), Velasquez rebounded with two brilliant starts and a win (12.2 IP, 1.42 ERA, 0.79 WHIP, 13 Ks). Despite this, he is still 16th worst with a .378 BABIP heading into a start against the Braves April 18.

The sleeper thesis on Velasquez relied on his ability to develop a better third pitch to balance his power fastball-slider. So far he's only thrown his changeup 5.8% of pitches, but preliminary results indicate an excellent 6.55 pitch value. He's also been leaning a lot more on his curveball (to varied outcomes), but that could be bearing fruit elsewhere during at-bats. Another key for Velasquez was harnessing his wildness. A much-improved BB/9 (2.35) and K/BB (4.25) has led to more strikeouts and a Z-Contact% of 81.8% (from 86.6%). We argued Velasquez' 2017 20.8% HR/FB rate was fluky, keeping hitters off-balanced will prevent them from sitting on softballs down the middle.

Like our RotoBaller colleague Elliott Baas, some owners remain dubious on Velasquez, but continued progress coupled with a lower BABIP could alleviate those concerns in short order.

Other possible outperformers: Jon Gray (COL, .391 BABIP), Marcus Stroman (TOR, .386), Lance McCullers (HOU, .372)

Bearish Flags

Reynaldo Lopez, Chicago White Sox (0-2, 1.42 ERA, 1.00 WHIP)

I love breakouts, especially young fireball-chucking prospects like Reynaldo Lopez. Despite two tough losses, the 24-year-old has been fantastic in three quality starts (9.95 K/9) including a 10-strikeout highlight reel April 16 in Oakland. I picked up some shares myself across various leagues, so it pains me to feature Lopez as our top negative regression candidate. But the analysis centers around BABIP, and Lopez ranks second luckiest at .154.

The first incongruity is his 4.29 xFIP that compares disparagingly to the microscopic ERA. Where BABIP really masks Lopez' inefficiency is the WHIP. Underneath the sparkling hood, Lopez possesses a 5.21 BB/9 that is 11th worst in the majors. Incredibly, his BAA of .127 has wholly accounted for the ongoing WHIP revelation and probably more. Although his track record is limited, the current 16.7% LD% pales to his career clip of 21.7%. While his strikeout prowess does affect LOB%, Lopez has stranded baserunners at an unsustainable 92.6%.

His ownership tag (43%) is sure to rise in the coming days. I'm also tempted to let the good times roll for now. But be aware the hits could start dropping at any time, and Lopez is likely in for a few clunkers. With the hype intensifying and stock at an all-time high, timing could be ripe for skeptical owners to float a trade before Lopez faces the Astros this weekend.

Sean Manaea, Oakland Athletics (2-2, 1.63 ERA, 0.72 WHIP)

Is this the year Sean Manaea puts it all together? The early indications appear so. Dismissing a speed bump against the Dodgers on April 10, the former first-rounder has been mostly great in four starts. Manaea has gobbled up innings (27.2) and boasts a solid 5.00 K/BB. However, Manaea has also enjoyed the benefit of a .169 BABIP so we must play devil's advocate.

Manaea's lack of strikeouts is the primary caution flag. His 6.51 K/9 is below an underwhelming 7.72 rate for his career. His fastball velocity hovers at 90.1 MPH, affirming his inability to overpower batters. Manaea has seemingly been extra lucky. His poor 36.0% Hard% fails to reconcile with the low BAA and BABIP. Like Lopez, Manaea has enjoyed a below-normal 14.7% LD%, which generates the highest batting average by a significant margin. To add an anchovy atop your rotting cake, Manaea has a LOB% of 100%! Sadly, the only way from there is down.

Manaea's eventual decline shouldn't be a doomsday event. He's a vaunted young arm with impressive control and decent track record through two-plus seasons. Manaea's 3.72 xFIP is better than most qualified pitchers, so there's a degree of success he's dictated amidst the strong run-to-date. The current top-30 fantasy numbers just may not last a full season. Manaea's next opportunity to defy the forces of mean reversion comes this weekend at home against Boston.

Other potential underperformers: Jakob Junis (KC, .170 BABIP), Chase Anderson (MIL, .196), Andrew Cashner (BAL, .237)

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