MLB.com keeps a leaderboard of the fastest pitches thrown each season, as measured by Statcast. More illustrative than the results of that leaderboard is the existence of the “Chapman Filter.” In 2017, Aroldis Chapman threw the 23 fastest pitches in baseball and 44 of the top 50. Boston’s Joe Kelly and Pittsburgh’s Felipe Vázquez got into the top 50 three times each. Nobody else appears on the first page of results.

It’s a testament to Chapman that he dominates the leaderboard to such an extent that his presence makes it totally useless. MLB had to create an “everyone else” statistical category, which the league hasn’t had to do for other outliers like Aaron Judge and exit velocity or Billy Hamilton and sprint speed.

This year, though, MLB is going to need to filter for someone else: Cardinals right-hander Jordan Hicks. Although he’s thrown just 83 fastballs all year, Hicks has thrown the eight hardest pitches of the 2018 season.

At this point, unless you’re an obsessive prospect hound or preparing for your super-deep keeper league draft, you might be wondering: Who the hell is Jordan Hicks?

That’s a fair question. Hicks, a 21-year-old rookie from Houston, was a third-round pick in 2015, signing for $600,000, slightly above slot value. He’s not an unknown; he was sixth on the Baseball Prospectus Cardinals top-10 prospect list this past offseason and 11th on FanGraphs’ Cardinals list. Anyone who throws as hard as Hicks does is going to generate some attention. But while Hicks pitched well in two minor league seasons, he hadn’t put up eye-popping strikeout numbers in his 31 career starts and topped out at high-A. As of the end of 2017, it was: So far, so good, but call us when you develop a third pitch and throw strikes consistently. FanGraphs stuck a 2020 MLB ETA on Hicks, while BP said: “2019, maybe sooner if the Red Birds need an high-powered relief arm.”

“Sooner” turned out to be “immediately.” Hicks impressed in training camp, with eight strikeouts and two earned runs allowed in 7 2/3 innings, and the Cardinals took him north. He got an inning’s worth of work on Opening Day, and his first pitch was clocked at 101 miles per hour. Since then, he’s made seven appearances totaling 8 1/3 innings, striking out six and walking six, but allowing just a single unearned run.

At 6-foot-2 and 185 pounds, Hicks doesn’t have a fireballer’s physicality. He doesn’t have Chapman’s long levers or Craig Kimbrel’s squat sturdiness. He’s springy, with a wonderfully huge 1960s-style leg kick, but kind of skinny. Not that it matters. Hicks’s fastball, which he’s thrown about three-quarters of the time so far, is obviously his biggest weapon. At an average of 99.1 miles per hour, not only is it the hardest pitch in the majors this year, but it also has more than 9 inches of arm-side break.

Per @statcast, @Jhicks007 has been tossing some heat!



Fastest pitches, 2018

1. 101.6 mph -- J. Hicks, 3/29

2. 101.0 mph -- J. Hicks, 4/1

3-T. 100.9 mph -- J. Hicks, 4/1

3-T. 100.9 mph -- J. Hicks, 3/29

5-T. 100.8 mph -- J. Hicks, 3/29

5-T. 100.8 mph -- A. Chapman, 3/29 pic.twitter.com/TzS5Jwmjaq — St. Louis Cardinals (@Cardinals) April 2, 2018

That means Hicks’s fastball runs in on right-handed batters’ hands—a scary enough proposition when it’s coming in at 100 miles per hour—and that he teases lefties with it while fading the pitch off the plate. Hicks’s slider comes in at the mid-80s with mostly horizontal break, seven and a half inches to Hicks’s glove side. That difference in the horizontal break between the fastball and slider, nearly 17 inches, is about the width of a regulation MLB plate.

Hicks’s fastball is special enough on its own, but it’s also eye-catching that he’s pitching high-leverage innings in the big leagues at age 21, with fewer than 200 professional innings under his belt, and no experience above A-ball. Although, it’s not as unusual as you might think.

Pitching in the big leagues is a phenomenally complicated proposition, at least for starters. It takes a long time to build up the physical endurance and the (at least) three-pitch repertoire to throw 200 innings a year, and then it requires tremendous cleverness to figure out two, three, sometimes even four different ways to get an individual batter out in a single game.

A one-inning reliever’s job is comparatively simple. Pitchers who have certain physical gifts—such as a 100 mile-an-hour fastball—can more or less just go up there and throw the shit out of the ball for 20 pitches at a time. And if hitters start to track the heater, they can just throw the shit out of the breaking ball. It doesn’t take that much development to learn how to throw the shit out of two pitches if you’ve got them.

The Cardinals’ closer for most of the past four years was Trevor Rosenthal, who ended the 2011 season in low-A. By July 2012, he was pitching out of the big league bullpen. Rosenthal, who was a position player in college, was developed as a starter for about two years, like Hicks, before he reached the bigs as a reliever just after he turned 22. Kimbrel had less than two years’ minor league seasoning before he reached the majors at age 21, and he was one of the best relievers in baseball from the moment he got to Atlanta.

While other closers from Ken Giles to Arodys Vizcaíno have gone from A-ball to the back end of a big league bullpen in 12 months, too, the most famous example is K-Rod. Francisco Rodríguez had a 5.38 ERA as an A-ball starter in 2001, debuted in the big leagues late in 2002 at age 20, and won five playoff games in relief that year as the Angels won their only World Series title. The Angels had an awesome bullpen that year led by Troy Percival, but it was K-Rod, who’d had all of 5 2/3 big league innings to that point, who became the most famous middle reliever in baseball history. He’s racked up 437 big league saves in the 15 years since, including an MLB-record 62 in 2008.

Hicks was years away from putting it all together as a starter. The Cardinals could’ve either left him in the minors another two or three years, in which time he might have developed into a mid-rotation starter. Or he might have ended up in the bullpen anyway—so why wait? Hicks can continue to develop against big league hitters—he still needs to command his pitches better before he becomes an elite reliever—and help the club now before becoming the closer next year when Greg Holland leaves in free agency. His rapid ascent is impressive and surprising, but it makes sense. It’s not nearly as impressive as breaking the Chapman Filter.