Watch J.A. Happ pitch, and you know he has to have a secret. The Blue Jays lefty throws a fastball with average velocity nearly three-quarters of the time, pitches in a tough home park, and somehow is a win away from 20 with an ERA better than three-quarters of baseball.

He must have a secret. And it’s not that he has a riding fastball: we’re getting more comfortable with that one and he’s a known rise-baller. Nor is it a secret with which Ray Searage blessed him. “I was pitching pretty good for two-and-a-half months in Seattle,” he responds at the prospect being counted as a Searage Surprise. “I wasn’t struggling to get outs.”

It isn’t a sexy secret, and of course it wouldn’t be. Happ’s never lit up the radar gun or dazzled anyone with his darting, diving stuff. And it’s not even his first secret regarding his stuff; he might have three secrets about the fastball. But it’s his newest one, and it’s been a big driver for his success this year.

The first secret was simply throwing the fastball more often. That’s something we’ve seen with him before, but it was something at which he arrived on his own in Seattle.

That realization came from accepting. “Accepting that I had been overthinking at times,” he said of his decision to throw the heater more in Seattle. He admitted that rates had something to do with it — “you do see the numbers and the results” — so the fact that his slider, change, and curve all had below-average whiff rates going into 2015 is meaningful. He decided to throw his best pitches better, a sort of reverse Corey Kluber.

Here’s perhaps a secret about a secret. I thought that throwing the fastball more was about getting into better counts and improving his walk rate, and he has been showing his best walk rates recently. But he pointed out that something interesting happens when you throw the fastball more: “Everyone is hitting off the fastball. At the same time, they get overanxious with the fastball if you throw it more.”

You can see that hitters are swinging more at Happ’s fastball as he throws it more. Hidden in that swing rate is a career-best reach rate on the fastball. Happ’s gone to his strength, and in the process, has made hitters anxious to hit his strength more often.

But most of this was true, or at least coming together, last year, or even in Seattle. What’s been his newest secret? The sinker. He’s using it more than a quarter of the time right now, more than he’s ever used it before.

The list of pitchers who’ve added a sinker is long. The list of pitchers who’ve added decent sinkers to an arsenal that heavily features a riding four-seamer? That list is much shorter. Here are the qualified starters who possess a riding fastball and also throw a sinker that features at least three inches more sink on their two-seamer (three inches is the average difference), and throw it at least 10% of the time: Happ, Jerad Eickhoff, Zack Greinke, Matt Shoemaker, and Yordano Ventura. Kenta Maeda and Robbie Ray are close.

Still, Happ zooms to the top of this list when judged solely by the difference in vertical movement.

Nobody in baseball has as much of a difference in vertical movement between his four-seam and two-seam fastballs. And this is something newish for Happ, but he can’t quite put a finger on when it happened. “They are drastically different pitches, and it’s just all about feel,” he explained. “I’m trying to get that good pressure on the four-seamer and spin it for some good backspin, keep my hand on top of the ball. The sinker is a little bit different. To me it almost feels like it’s coming off just one of the fingers and the pressure is different.”

Happ found this vertical movement on his sinker late in his first Toronto tenure, but he just didn’t feature the pitch as much until he came back. Again, he talked about feel when it comes to his choice to use the sinker. “Some days I have the feel, other days I go with my other stuff,” said the Blue Jay.

If you look across Happ’s line, you won’t find a plus ground-ball rate. The sinker itself does well there, though: a 60% ground-ball rate on a sinker is actually plus. He just doesn’t throw it enough to make it show up on his overall rate.

Also, the pitch might be setting up the four-seam, which has a double-digit swinging-strike rate. When I asked if having ride on the four-seam works when you throw the pitch low, Happ let us in on a little secret: “It doesn’t get as many takes.”

The data appear to bear that out. On the left is the swing rate on Happ’s four-seamer last year; on the right, the swing rate this year. Notice the darker shade of red just above the strike zone in this year’s version. Happ’s getting more swings in a location that’s more to his advantage than the batter’s.

So that’s maybe how Happ has gone to his best weapon more often and yet also has convinced hitters to swing at his pitches more often. A whopping five-inch difference between the four-seam and the two-seam means that, if you’re expecting one, and get the other, you will miss that pitch. That might be his newest wrinkle, but it doesn’t seem like such a secret, after all. It’s all there, tracked for everyone to see. Maybe there are no secrets in baseball.