Nick Anderson is Breaking Baseball

It’s no secret that Nick Anderson is one of my favorite pitchers. When he ran a near-50% strikeout rate for the first month or two of the year, only months removed from being traded by the Twins to avoid a roster crunch, I was hooked by the story. More than the story, I was hooked by his curveball, a mid-80s, 12-6 snapping thing that ate batters alive:

Of course, I wasn’t the only person to notice, not by a long shot: the 37% strikeout rate he ran with the Marlins was a top-10 rate in baseball, and that’s not exactly easy to fake. The curve clearly played, getting whiffs on 53.7% of swings, third-highest in baseball for a curveball, and it wasn’t just numbers on a spreadsheet either — you can’t watch that pitch to Carson Kelly above and not say “ooh that’s nasty.”

When the Rays traded for Anderson at the deadline, I was elated. Anderson wasn’t exactly a household name, but he is in my household, and it was quite a thrill seeing a playoff-contending team, one who employs a noted reliever discoverer, concur with me that Anderson was a monster. The Rays don’t quite have the same reputation as the Astros for improving pitchers, but they do have a reputation for getting the most out of relievers, and an unlocked Nick Anderson sounded amazing to me.

It’s safe to say that my excitement was high when Anderson first appeared for the Rays. The appearance didn’t get off to a great start; Andrew Benintendi smacked a low line drive into left field on a pretty good fastball:

Before I had time to worry, reality asserted itself. After a fly out by Sam Travis, Anderson did what he does best:

That last fastball was the hardest one he’s thrown all year. His fastball is already a marvel, with the sixth-most ride in baseball, and now he was sitting 96-97. Four batters, two strikeouts: this was the Nick Anderson I knew and loved.

But Anderson wasn’t happy with a 50% strikeout rate. He pitched two days later against the Marlins:

Then against the Blue Jays:

And after two rest days, against the Mariners:

Oh boy! Four games, 13 batters faced (I only showed the strikeouts, but all three of those were perfect innings), eight strikeouts. Anderson was going full Josh Hader all of the sudden, striking out more than 60% of the batters he faced. He even had the same physics-defying rising fastball, though without the wild release point and lefty funk on his delivery.

He wasn’t done yet. The Mariners came back for more the next day:

The Padres didn’t fare any better:

Six games, 19 batters faced, 14 strikeouts. Nick Anderson is breaking baseball right now.

Stats don’t mean much over such a tiny sample, but they’re so incredibly fun that I thought I’d tell you them anyway. Over those six games, his ERA is, of course, 0. His WHIP, if you’re into that kind of thing, is 0.17. He has a 73.7% strikeout rate to go along with a tidy 0.0% walk rate, leading to a -1.44 FIP (!) and a -0.78 xFIP (!!).

I’m not here to tell you that Anderson is suddenly a true-talent 0-ERA pitcher. I’m certainly not here to tell you that he’s a true-talent 75% strikeout rate pitcher. Neither of those things exist, and a lot of crazy things can happen in six games. I am here to say, however, that this run is downright ridiculous. Take a look at the best six-game strikeout rates in baseball this year:

I’ve excluded overlapping sets, as otherwise Anderson would also be fourth and Hader would be fifth. The point of this arbitrary cutoff and ranking isn’t to prove Anderson’s greatness. It’s a curiosity, a way to contextualize Anderson’s run. Without comparison, it’s hard to know what a good six-game stretch is.

Anderson’s stretch is obviously excellent by strikeout rate, but it looks even nuttier by FIP. Let’s run that six-game list back again, but this time ordered by lowest FIP instead of highest strikeout rate:

This recent streak is, quite simply, bonkers. No one has reeled off a run this dominant, this completely devoid of blemishes, all year. Anderson was as good a candidate for it as any: he strikes out a ton of batters and doesn’t walk many. He fills the zone, throwing both his fastball and curveball for a strike more often than league average for those pitches. He generates whiffs on both, and a fair amount of called strikes.

Anderson’s ERA hasn’t quite matched up to his FIP this year, and negative-FIP streaks aside, you might be tempted to attribute that to the hard contact he allows. Sorting by average exit velocity can be deceiving, because it doesn’t capture the distribution of batted balls, treating a dinger and a pop up the same as two weak fly outs, but Anderson allows a 94th-percentile exit velocity, where higher percentiles are worse for the pitcher.

A 94th-percentile exit velocity for a fly ball pitcher? That sounds dangerous! But that exit velocity number includes all batted ball types. Limit that to balls hit in the air, and he falls to 62nd percentile. He allows a 72nd-percentile amount of barrels per batted ball, which is bad but not disastrous. That’s the kind of rate you don’t want from a pitch-to-contact starter, but it’s totally fine for a high-octane reliever who ends half of his plate appearances with a strikeout or walk.

Put simply, Anderson is an elite reliever. He’s fifth in WAR, sixth in FIP, third in strikeout rate, and fourth in K-BB% among all relievers this year. If swinging strike rate is your indicator of choice, he’s fifth, and he has the 11th-highest whiffs per swing rate. Want to regress out home runs? He’s seventh in xFIP.

How does he do it with only two pitches? They are perfectly suited to each other. His fastball is nearly all rise, his curveball nearly all drop. Their spin is mirrored nearly perfectly. Imagine, if you will, a ball traveling towards the plate with no spin whatsoever. Anderson’s fastball rises at a 73.2 degree angle from that (using horizontal movement and vertical movement ignoring gravity, and with 0 as the right side of the horizontal axis), up and to the right. His curveball moves at a 249.9 degree angle, down and to the left.

The two pitches are almost perfectly 180 degrees apart, moving on the same axis in opposite directions. It is hell for batters’ perception, because they can’t pick up which is coming, and the two are separated by a huge margin. To get that offsetting movement, Anderson has to spin the ball more or less exactly the opposite way. The resulting spin is really hard to distinguish for batters, and spin mirroring is all the rage in pitch design these days.

What all of this means, more or less, is that Anderson’s success isn’t a fluke. His raw stuff is excellent on its own, and the two pitches pair together well. He’s a strike-thrower, a fly ball pitcher who doesn’t allow particularly hard contact on fly balls, the kind of reliever you can build a bullpen around.

This streak won’t continue. No one in baseball is as good in the long run as Anderson has been since joining the Rays. But for the moment, I’m enjoying it. Watching a great reliever at their dominant peak is thrilling, and we’re experiencing it in real time right now.