Deception is tough to evaluate but potentially crucial for pitching prospects. As Fangraphs' Eno Sarris wrote last year, Yusmeiro Petit has essentially built his career on his ability to hide the ball from the hitter. Petit's arm action keeps the ball behind his body as he winds up. Then, as he throws, the ball disappears behind his elbow, resulting in what Sarris refers to as an "invisiball." The action is a major reason why Petit became a key contributor on a World Series team last year despite averaging just 88 mph on his fastball.
Now imagine if Petit could throw 95 mph. Picture it? If not, you might not have to look much further than Dodgers prospect Jose De Leon.
It's unfair to throw a one-to-one Petit comparison on Jose De Leon's delivery, but there's some notable similarities between the Giants' hurler and the 22-year-old Dodgers prospect, who was promoted to Double-A Tulsa on Monday.
Like Petit, De Leon manages to hide the ball behind his body longer than most pitchers. The right-hander keeps his hand behind his right hip after breaking the ball from his glove, then cocks his arm by sliding the ball up along his right side, keeping it out of the hitter's view. You can see this motion in the video below.
What makes Petit's particularly deceptive, though, is that he manages to hide the ball behind his throwing elbow as he delivers, making it look like the ball appears out of nowhere to the hitter. We don't have indisputable video evidence that De Leon does the same, but based on the MiLB.TV video embedded above, this slow-motion YouTube clip and anecdotal evidence by those who have watched him, it seems that De Leon might be replicating Petit's "invisiball" with more impressive stuff. At the very least, he's doing something similar.
"Part of his success is that he hides the ball really well," said Rancho Cucamonga pitching coach Bill Simas. "Some people have a knack for that. It's hard to explain. He hides it behind his body until that release."
De Leon has picked up as much helium as any prospect in baseball over the past 12 months, and deception is only part of the reason why.
The Colegio San Antonio (Puerto Rico) product was a 24th-round pick in the 2013 Draft and was well off the prospect radar as late as June 2014. That's when he began to dominate with Rookie-level Ogden, where he struck out 77 batters over 54 1/3 innings while posting a 2.65 ERA. After a late-season bump to Great Lakes, De Leon struck out 42 in 22 2/3 innings and managed a 1.19 ERA.
By improving his conditioning and tweaking his delivery, De Leon went from throwing in the high 80s and low 90s to consistently sitting 93-94 and hitting 95 with regularity. He maintained good velocity separation between his fastball and changeup, and his slider sharpened from the extra hand speed. By sliding from the third-base side of the rubber to the middle and straightening his stride, De Leon stopped throwing across his body and discovered he could locate to both sides of the plate, as well as up in the zone.
This year, De Leon has continued to dominate in the Class A Advanced California League. In seven starts with Rancho Cucamonga, the right-hander posted a 1.67 ERA. His 13.9 strikeouts per nine innings are second in the Minors to the Cardinals' Alex Reyes (featured earlier this season in this space).
The right-hander's changeup is his best off-speed pitch right now, according to Simas, which led to particularly dominant numbers against left-handed hitters. De Leon held lefties to a .194 average and posted a 30-to-2 strikeout-to-walk rate against them as a Quake, primarily working a fastball-changeup combo against them.
His slider is also a promising offering, getting solid-average grades from MLB.com's Prospect Pipeline team. The 22-year-old throws all three pitches for strikes and simply needs more experience against advanced hitters before he'll be ready for a Major League look -- something that could come later in 2015.
"I think he just needs to pitch more, see more batters," Simas said. "Learn a bit more how to use the weapons he has."
Armed with three above-average pitches, solid command and a growing track record of dominance, De Leon is poised to fast-track to the Major Leagues, something baseball people never saw coming. Then again, that's something of a specialty for the 22-year-old.
Nationals SS Wilmer Difo, Double-A Harrisburg/MLB Washington: Speaking of players who broke out in 2014, Difo went from a relative non-prospect to one of the most enticing talents in Washington's system last year. Difo showed five-tool potential with Class A Hagerstown, hitting .315 with 14 homers, 49 stolen bases, and promising defensive skills -- one South Atlantic League manager projected above-average glove work from Difo down the road at short. The 23-year-old opened 2015 at Class A Advanced Potomac, posting a .919 OPS in 19 games, then more or less replicated those results in 14 Double-A games before earning a surprising callup to the Majors on Tuesday. It's hard to see where Difo fits on the Major League roster, so the Dominican's time in the Minors might not be over -- expect him to be the odd-man out when Anthony Rendon returns from the disabled list. Still, the promotion signals just how much confidence the Nats have in Difo's abilities despite his lack of upper-level experience.
Rays RHP Brent Honeywell, Class A Bowling Green: Everybody's favorite screwballer has said a few times this year that his goal for every start is to throw a no-hitter or perfect game. He came close this week, logging seven hitless frames before the Hot Rod bullpen allowed a base knock in the eighth. The 20-year-old has an innate ability to process coaching and apply advice. Tampa Bay first worked with Honeywell to improve his changeup, and it quickly became an above average pitch. The team then gave him instructions to improve his fringy curveball, and suddenly it's become an above-average offering, too. Add in an above-average fastball, the screwball and Honeywell's plus makeup and competitiveness, and the 2014 second-rounder is rapidly emerging as a no-doubt Top 100 prospect.
…And one not
Reds 3B Taylor Sparks, Class A Advanced Daytona: The 2014 second-rounder was expected to have some swing-and-miss in his game, but he does have above-average raw power and solid third-base defense on which to fall back. Sparks' poor plate approach has kept us from seeing the power so far, and his defense at third has been shaky as well. The UC Irvine product is striking out in 38.5 percent of his plate appearances and has just six walks in 36 games. That's led to a .230 batting average, and he's only hit three homers and six doubles. Defensively, Sparks has a lackluster .878 fielding percentage -- which, despite the flaws inherent in fielding percentage, is below average by a few standard deviations. You don't write off a prospect like Sparks based on a poor month-plus of action, but it hasn't been the smoothest transition from college to pro ball for the 22-year-old so far.
Jake Seiner is a contributor to MiLB.com. Follow him on Twitter at @Jake_Seiner.