Trevor Oaks hopes to stand tall on a big-league mound this season. In order to do so, he’ll need to regain his worm-killing ways. The 24-year-old right-hander relies heavily on his sinker, which didn’t do its usual diving last summer. One year after logging a 64.5% ground-ball rate at Double-A Tulsa, Oaks saw that number tumble to 50.8% with Triple-A Oklahoma City.
Oaks is a member of the Royals now, having been acquired by Kansas City from the Los Angeles Dodgers in January’s Scott Alexander deal. He believes that his old bread and butter will be accompanying him to America’s heartland. Not only is he fully recovered from an oblique issue that dogged his 2017 campaign, he was able hit the reset button on his mechanics over the offseason.
And then there are the lessons learned. Despite not having his best stuff, Oaks put up a solid 3.64 ERA in the hitter-friendly Pacific Coast League — and a veteran teammate deserves some of the credit. When words of wisdom were in order, Justin Masterson was there to provide them.
Oaks on Masterson’s influence: “Baseball-wise, Masty talked to me a lot about tunneling and making sure that everything comes out on the same plane. Even though we have different arm slots, the same principles apply. His slider is like a Sergio Romo slider, so that wasn’t exactly in my bag of tricks, but with his sinker… he turns the ball over a little bit more.
“I was struggling to find consistent movement. In years past, it’s always just kind of been a natural pitch for me, so I hadn’t really thought much about it or really tweaked around the grips too much. So while I was going through that period of struggle, he was able to show me things. It was like, ‘Hey, why don’t you try this?’
“A lot of it was just little tweaks here and there, from stuff he had learned over the course of his career throwing the sinker. And he was also kind of calming me down. He’d say, ‘Hey, don’t freak out if it’s not your best stuff that day.’
“I think that’s why I still had a decent year. While I didn’t have my best sinker, I was still able to go out there and compete. I had the confidence to be like, ‘I can get these guys out, even without my best sinker, and then once that pitch comes back for me, I can really take off.”
On the keys to a good sinker: “For me, it’s kind of a combination of staying on top of the ball and the pronation. I had recently started throwing a cutter, and I think the cutter kind of changed the way that I released the ball on my sinker. Instead of being on top, I was behind it a little more and not staying through the pitch. I was kind of coming across my body instead of staying true all the way to the plate.
“Some of the adjustments I made this offseason should help. I moved my thumb underneath the ball a little bit more, and all the sink totally came back. I also started doing a little of the weighted-ball program while the Dodgers were still directing me on my career. I felt that helped me be a little more athletic and get that rhythm back to my pitching motion. So far I haven’t had a day in my offseason where the ball isn’t driving like crazy. I’m excited to have that pitch back, with the confidence that the ball will be doing what I want it to do.
“On the pronation… it’s not like I intentionally try to pronate. It’s more that my arm just naturally does that. But again, staying through the pitch and not cutting it off short… sometimes, over the course of your career, you’ll notice that your throwing motion will kind of change. Because of the cutter, I was kind of coming across my body a little more, and this offseason allowed me to reset that. Now I’m throwing through the ball again, which has given me that pronation back.”
On his sinker grip: “It’s your standard two-seam. I think the only difference might be that I have have my thumb on the diagonal corner of the horseshoe. I try to keep it more underneath, which helps my fingers get on top of the ball better.
“My fingers are inside the two seams, and then my thumb I put directly underneath the horseshoe on the other end. It’s more like I’m splitting the ball in half, versus kind of off to the side. Masty has more of an offset two-seam grip that is similar to a one-seam. It’s just a little bit higher on the ball, and then his thumb is more on the side. If you watch him throw, he really gets over the top of it.
“He’s a little more lateral plane. He comes across his body, whereas I’m more up and down. I think the struggles he had with his command last year were about finding that arm slot and release, whereas I lost the depth on my sink.”
On his cutter and slider: “I pretty much use my cutter and my slider with the same grip, but with one I try to get on top of more and roll over to get the depth, and with the other I kind of stay behind it. So maybe [my cutter] is just a variation of my slider? Moving forward, I think I might just call it that.
“It’s basically just a slider with more backspin and coming in at 87-89. Then, if I want the downward plane and the axis-like spin, I can turn it over and make it have some drop to get underneath a barrel.
“I used to throw a curveball, too, but we bagged that. It came out on a different plane and wasn’t something that was effective. It was just kind of a get-me-over, so I figured why not just throw my slider, because it’s going to be more effective anyway.
“Masty’s slider is like Romo’s in that it moves a ton. Sergio Romo has one of the best sliders in the game. I remember him being with the Dodgers in spring training and working with Kenley [Jansen]. He’s like the master of that pitch. He can make it bigger, or he can make it shorter, depending on what he’s reading from the hitter. I think Kenley really liked that.”
On changing organizations and addressing a weakness: “I haven’t gotten much of a chance to talk to the Royals coaches and front-office guys yet, but the Dodgers are very involved [in pitching analytics]. As a player, I kind of put that out of my mind, though. I try to just worry about winning the game. I think that attitude should serve me well, because however much the Royals value that, when you get right down to it, what everybody wants is to win.
“I know my weaknesses, and the Dodgers made me aware of some things I needed to work on. One in particular was facing left-handed hitters, because of my splits.
“When I went to Arizona to rehab, I asked [pitching analyst, and now farm director] Brandon Gomes, ‘Hey, I want you to analyze me in front of all the hitters and see what the scouting report would say.’ I wanted to hear which areas the hitters are going to try to expose. Facing left-handed hitters was one of the things they talked about.
“I need to get my changeup going. It’s pretty well known that I’m not going to go out there and dilly dally around the zone. I’m going to pound the zone, so the hitters are going to be aggressive. With that, I need to make sure I stay down and execute my pitches, and mix it up a little bit.”
On his new changeup grip: “I’ve never really had a… I would say my changeup is my fourth-best pitch. If I’ve needed to throw an offspeed pitch for a strike, I’ve wanted to go with something I feel more confident in. But the work I put into it this offseason… I switched up my grip a little bit. I was throwing a four-seam changeup — it felt better in my hand, and I had better command with it — but now I’m going to be throwing a two-seam changeup.
“I’ve been really happy with the speed differential I’m getting — about 10-12 mph — so I’m heading in the right direction. The last tweak will be to get the command down. Spring training is where everything kind of clicks. That’s where you get hot. You’re throwing on a daily basis, and that consistency is going to make everything better.
“Greg Maddux was kind of helping me out [last year]. He was a big promoter of putting pressure on your ring finger and using that as a control. That started me thinking about how I throw the ball. As a sinker guy, my control fingers are my index and middle — primarily my middle finger, because that’s the last one that leaves the ball. Instead of putting pressure on my ring finger, I switched it and put it on my middle finger.
“That really helped. I feel like I was staying through the ball more. I had spin that was more similar to my sinker and had more of that two-seam action. When I say ‘spin,’ I’m referring to true spin. Sometimes you’ll see guys pronate too early and the spin comes out weird, and it doesn’t look like their fastball spin.”
On major-league vs. minor-league baseballs: “I would say the major-league ball has a sharper break than the minor-league ball. It’s not as big. The spin is tighter because the seams aren’t as high. And when you don’t throw it correctly — if you kind of yank a pitch — it isn’t forgiving at all. It will just shank over there.
“A minor-league ball doesn’t tend to do that. It will still sink a little bit or maybe just stay straight. I feel the big-league balls carry better, too. When they’re hit, they carry better because it’s the harder ball and it spins more.
“And there has to be a reason why a lot of guys were having trouble with their sliders during the World Series. For me, it’s hard to believe that you can throw 200-plus innings during the season and then get to the World Series and have no feel for your slider. I don’t know if the ball was different, but I do know that guys were talking about it.”
On front-hip sinkers and pitching to contact: “A pitch I’ve been working on a lot is a front-hip sinker to lefties. You start it off the plate and let it break onto the corner. That’s something I’m getting more comfortable with — commanding the inside of the plate to lefties — which has actually been a work in progress for a while. It’s something they brought up in spring training, but not having my best sinker last year kind of put a halt to those plans.
“I’ve also… I don’t want to give up too many my secrets here, but moving around on the rubber is something I’ve tinkered with. I feel like that can be a weapon in my back pocket. I’m always trying to work on stuff. I know I’m not the biggest strikeout guy, but there’s value in guys who attack the zone and keep a good pace to the game. I think that helps your defense.
“The Dodgers have a really good strong-mind program, and I clicked really well with A.J. LaLonde, their main psychology guy, but I also know what works for me. I have to simplify everything and just go out there and attack. Either I’m going to give up a lot of runs and come out of the game early, or I’m going to roll through the lineup. Whatever happens, it’s because I’m going to take it to them. I’m not going to be timid.”
David Laurila grew up in Michigan's Upper Peninsula and now writes about baseball from his home in Cambridge, Mass. He authored the Prospectus Q&A series at Baseball Prospectus from December 2006-May 2011 before being claimed off waivers by FanGraphs. He can be followed on Twitter @DavidLaurilaQA.