Few pitchers in baseball have a fastball as compelling—or as complicated—as that of Cubs reliever Carl Edwards Jr. For one thing, his four-seam fastball has the highest average spin rate of any in MLB, by a mile.

Average Four-Seam Fastball Spin, 2017 (Min. 500 Thrown)


Spin Rate (RPM)

Carl Edwards Jr.


Matt Bush


Justin Verlander


Cody Allen


Yu Darvish


The gap between Edwards and second-ranked Matt Bush in this metric is slightly larger than the gap between Bush and 27th-ranked Ariel Miranda. That’s how much the slender right-hander stands out for his ability to create spin on his heat. In general, higher spin on a fastball means more riding, rising action, and more swings and misses. Indeed, our PITCHf/x leaderboards show that Edwards gets whiffs on 32.5 percent of all swings with his heat, fifth-highest among the 123 right-handers who have thrown at least 500 four-seamers this year.

Edwards also gets more grounders than the average pitcher on his fastball, and for a high-spin, four-seam guy that’s unusual. Of the four guys immediately trailing Edwards in the table above, the highest ground-ball rate on the four-seamer belongs to Darvish, at 35 percent. The rest are all under 30 percent. Edwards comes in at 42 percent. That’s because, as Eno Sarris has been helping us all understand for a while now, ground balls come from horizontal movement—from being able to slide up the barrel, or out to the end of the bat, disrupting a hitter’s swing plane and foiling his effort to square up the pitch.

Unlike the other four guys above, Edwards is an outlier in that regard, too. His fastball has more cutting action, more movement to the glove side (in the case of the right-handed Edwards, away from a right-handed batter), than any other right-hander’s four-seam heat. Sonny Gray, who shares a top-shelf sheer spin rate and this cutting action, gets tons of grounders on his fastball, even more than Edwards does. It seems as though the unique axis of Edwards’ fastball spin is helping him, in a way distinct from (but perhaps just as important as) the total amount of spin he imparts on the pitch.

That’s why it’s worth asking whether what Edwards throws is really a four-seam fastball at all. Cubs radio commentator Ron Coomer makes innumerable references, during every Edwards appearance, to his cutter. Rookie utility man Ian Happ called the pitch a cutter during an interview in which both he and Edwards were participating last month, and Edwards didn’t correct him.

If you decided to call the pitch Edwards uses as his only fastball a cutter, it would be easily the hardest one thrown by any right-hander. It would rank 43rd out of 58 (using 200 cutters thrown as a minimum) in cutting action on the horizontal plane. It’d also have more rising action than any cutter in the league, and fall into roughly the 80th percentile for whiff rate on swings, rather than being in the 96th percentile as it is when sorted among the fastballs. It’d have the highest average spin rate of any cutter, too, though by a slimmer margin. (Darvish, Tyler Chatwood, and Kenley Jansen all throw cutters with average spin rates north of 2,600 RPM.)

It’s a semantic discussion, of course. Whatever one chooses to call the pitch, it stands out, and his curveball plays very well off of it. Despite average movement, Edwards’ hook induces more whiffs per swing than all but five other right-handers’ curves, yields a great ground-ball rate, and generally gives hitters fits, because he matches his release point and arm speed on the pitches well and has a naturally deceptive delivery. (It also helps that batters have to plan on catching up to a cutting fastball that reaches the upper 90s, and that Edwards gets good extension on each pitch, shortening the time they have to recognize either offering.)

Also, whatever one chooses to call the pitch, Edwards needs to throw it (and the curve, especially to right-handed batters) for a strike more often if he wants to take the one step remaining in front of him, from great reliever to truly elite reliever. It should surprise no one who has seen Edwards pitch to learn that he's in the 11th percentile for Called Strike Probability, the stat we use to measure a pitcher’s proclivity for working in and around the zone. And it should surprise no one who has read this article (all that spin and horizontal movement, from a fairly high arm slot!) to learn that he’s in the 21st percentile for Called Strikes Above Average, our estimator of the degree to which a pitcher contributes to getting called strikes on the edges of the zone (and for some, a proxy for command).

Some of that is mental. Edwards has admitted as much. He loses the strike zone altogether at times. At other times, his inability to throw the curve for a strike makes it too easy for batters to foul off the (cut) fastball, until they get one they can let go on the edges and force a walk. If he could develop a better changeup, a pitch with some arm-side movement to counter the third-to-first flow of both the heat and the curve, it might help, but he really needs only to keep honing his command, monitoring his breathing, and keeping that filthy fast thing he throws humming.

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Easiest gas since Kerry Wood.