As the season approached, I found myself intrigued by the Oakland starting rotation. That being said, among the starters, I was least interested in Kendall Graveman. Andrew Triggs? I’m all over that. Jharel Cotton? You better believe it. Kendall Graveman? Ehh. He didn’t do much for me. That was my mistake.

This is today’s second Graveman post on FanGraphs. I wrote the first one a few hours ago, wherein I discussed that Graveman seems to be experiencing a velocity spike, on the heels of a 2016 velocity spike. That fascinates the hell out of me, but something still felt incomplete. So here I’d like to revisit what Graveman has going on, because I’ve found a fun point of comparison. Why care about Kendall Graveman’s velocity? Because you could say his sinker has leveled up.

To quickly review, in his opening-day assignment, Graveman showed off some new heat. Here’s an example of something he did to Cameron Maybin:

That’s a sinker around 96. A few times, Graveman flung sinkers around 97-98. His average for the evening was close to 95, and this wasn’t just a random tracking error, because Graveman had been clocked around similar levels toward the end of spring training. Graveman’s arm strength has consistently increased since he got to the majors, and now he looks like a legitimate power pitcher. A power pitcher who leans heavily on his sinker and cutter. Those two pitches accounted for nearly everything Graveman just threw, and he’s had a similarly simple mix for some time now. As the sinker goes, so goes Graveman.

So let’s think about this sinker. Is there another sinker that looks about the same? There are a few, actually, but I’d like to call your attention to one. In the table below, you see one guy’s 2016 sinker. Then you see Graveman’s 2017 sinker velocity, with his sinker movement since last year’s All-Star break (I don’t completely trust the opening-day movement readings alone). I’ve also included some batted-ball data from Baseball Savant. Let’s advance to the fun part:

A Sinker Comparison Pitcher SI MPH SI Horizontal SI Vertical 2016 SI EV 2016 SI LA Aaron Sanchez 95.5 -9.0 6.7 92 4.4 Kendall Graveman 94.8 -8.8 6.1 91 4.8 SOURCE: Brooks Baseball

Kendall Graveman is a sinker-ball righty. Aaron Sanchez is a sinker-ball righty. Last season, their sinkers already generated similar batted balls, on average. Now Graveman’s sinker has gotten harder. It’s nearly matching the Sanchez sinker in average speed, and if you look at Baseball Savant’s perceived velocities, last year Sanchez lost three-tenths of a tick, and Graveman gained four-tenths. That would eliminate the whole velocity gap. By horizontal movement, the pitches look similar. By vertical movement, the pitches look similar. Graveman gets a bit more sink. Maybe that matters.

This is Aaron Sanchez’s sinker striking out David Ortiz:

Whenever I run any of these pitch comparisons, I have to remind people that there’s a lot that goes into a pitch’s success. Movement and speed go a long way toward determining how a pitch does, but those traits say nothing about location. More, those traits say nothing about any level of deception. I don’t know what it looks like to see Graveman’s sinker from the batter’s box, and I don’t know how that compares to the experience of facing Sanchez. But at least in general, Graveman has closed the gap. Kendall Graveman’s sinker resembles Aaron Sanchez’s sinker, now that it’s picked up some more zip, and you’ll recall that Sanchez’s sinker is one of the best in the league.

Here’s a selection of last year’s pitch-type run values. Zach Britton, to no one’s surprise, threw the most effective sinker. Jake Arrieta came in second, and Chris Sale came in third. Sanchez shows up in fourth, a testament to the strength of the pitch that got Sanchez to the majors in the first place. There were never any questions about Sanchez’s sinker. There were questions about his control, and about the rest of his repertoire. Sanchez figured out how to pitch off of his sinker, and he turned into a quality starter. He might be the Blue Jays’ ace.

A difference between Sanchez and Graveman is how they fill out their repertoires. Sanchez has a fine curveball, and he’ll work in a changeup every 11 pitches or so. He also throws a four-seam fastball to change up the look. Graveman has a changeup, and he has a slider, but he’s mostly sinker/cutter. He’ll also mix in an occasional four-seamer. It’s not like these two pitchers are twins.

But Graveman might have better command. And we’ll still have to see how his pitch mix evolves, now that he could have this new arm strength. I don’t know how heavily he’ll lean on the sinker. I only know how heavily he leaned on it on Monday. He didn’t have much reason to change things up. Aside from one swing by the best baseball player in the world, Graveman skated through more or less un-punished. It was easy to see what made him so difficult.

I really am trying not to get ahead of myself. Graveman has started one game this season, and there are going to be plenty more. I don’t know to what extent he’ll sustain this second velocity spike. It’s going to take more time in order for Graveman to prove that he can really miss some bats these days. But opening day is all about finding reasons to get excited, right? There’s reason to get excited about Kendall Graveman. He already threw a good sinker, but now it looks more and more like one of the best sinkers in the league. Aaron Sanchez’s sinker is a pretty good role model.