North Shore Tavern Mound Visit: Selby double dips with spin

The next pitch, Selby went to the curveball. This one was up a bit again, but more by design. The result is as pretty a called third strike as you'll see:

Now the general rule of thumb with Selby is the slider is more a pitch to run away from right-handers and the curveball is the breaking ball for lefties, but he can throw both breaking balls regardless of which batter's box the hitter is in. And when he has those breaking balls at his disposal, he can tunnel the pitches enough to freeze the hitter:

"That's how he can weaponize it," Derek Shelton said about his breaking balls. "And I'm not saying he's always going to finish with the curveball. But, when you have two different ones and they have two different shapes and you're able to spin them like he does, the first time the hitter sees the other one, it kind of locks you up a little bit like 'whoa, that one didn't look like the other one.' "

Selby's major-league career is three outings old, two of which went very well for the rookie with a clunker in the middle. It's too soon to look to far into his results, but the peripherals that made him a darling in the Arizona Fall League last year and forced the Pirates' hand to add him to the roster have translated to the majors. Chief among those traits are his spin.

In the majors, Selby is averaging 2,620 RPM of spin on his slider and 2,715 RPM on his curveball. That leads the team in spin on pitchers currently on the 40-man roster (Robert Stephenson has the edge on both pitches and Wil Crowe does as well with the slider). Spin alone doesn't make a pitcher, but it's a great tool to work with. Or in Selby's case, tools.

"The rarity of seeing guys that pitch in the bullpen that have multiple offspeed pitches that are effective, I think that's one of the reasons we like him," Shelton said.

Entering play Saturday, there have been 523 pitchers league wide who threw at least one breaking ball in relief. Of those 523 pitchers, just 16 have a slider and a curveball average 2,600 RPM or more of spin.

This is admittedly not an absolutely perfect list because I'm omitting cutters (velocity spin can behave differently) and there are still a handful of position players who are counted as relievers this way (though filtering it through breaking balls does cut down that total significantly). But as a general rule of thumb, only about 3% of relievers have a curveball and a slider with that much spin. That's rare air for a rookie with three outings under his belt.

That spin can come with control issues, something that facilitated his push from starter to reliever in the minors. That popped up again this year with Class AAA Indianapolis, where he walked 22 over 30 1/3 innings, including six over his last three outings in the minors.

But if he can locate those breaking balls for called strikes, he'll be able to earn whiffs off spin that dives out of the zone.

"It came with time, but it's more trust than anything," Selby was telling me. "Knowing that what I have is good enough to get guys out at this level and just trusting that to put it in the zone so I can get swing and miss and light contact."

If he does that, Selby has the potential to be a leverage reliever. The Pirates had plenty of Rule 5 eligible relievers this past year, most of which were left unprotected and eventually passed on. With his spin, it would make sense for a team to take a flyer on Selby, which is why the Pirates rostered him.

It took him a little longer to get up to the majors, and a reliever isn't going to have the same impact as a position player, but there's upside here.

"I’m just excited to be here and play with the guys I’ve been playing with since 2018," Selby said. "It’s exciting to see all of us up here. I think this is going in the right direction, for sure."