Marcus Walden is a 30-year-old rookie with a 5-0 record, a 1.46 ERA, and a spiked-grip slider that helped rescue him from minor-league purgatory. The story behind the pitch is one of avoidance-turned-desperation, with a healthy dose of studiousness thrown in for good measure. Walden has thrown his slider 41.6% of the time this year in 24.2 innings out of the Boston bullpen.
The righty’s journey to the big leagues was a meandering one. Drafted by the Blue Jays in 2007, Walden subsequently saw time in the A’s, Reds, and Twins organizations. He also spent a summer toiling in the independent Atlantic League. The Red Sox signed him off the scrap heap prior to the 2017 season, but even then his prospect status was tenuous at best. Twenty-six pitchers saw action for the AL East club that year, yet Walden remained in Triple-A.
Walden finally made his MLB debut last April, but his time at the top was short-lived. Sent down in May, he stayed on the Pawtucket roster throughout the remainder of the campaign. This year has been a different story. Walden has been one of Boston’s best relievers — his aforementioned numbers are augmented by a 10.95 K/9 and a 2.46 FIP — and again, his slider is a big reason why. I talked to Walden about his signature offering prior to a recent game.
David Laurila: Your go-to pitch is a slider. What is the story behind it?
Marcus Walden: “I didn’t start pitching until my senior year of high school. My freshman year [at Fresno City College] — the one year I went to school — I was throwing a four-seam fastball and a slider. Now I’ve gone back to that same style of a slider, although with a little bit different grip that I learned from Chandler Shepherd, in 2017. And watching Craig Kimbrel was a big help. I watched him closely, especially in spring training of ’17 and ’18 when he was throwing his live BPs. I talked to him a little. It was, ‘All right. What kind of shape are we trying to make with this pitch?’ He throws a knuckle slider, and that’s what I throw now.”
Laurila: Why did you start spiking your slider?
Walden: “I was hoping to take a little bit of velocity off. I was throwing it at 88-89 [mph] roughly, but it wasn’t real tight. It wasn’t real sharp. So I went to the spike. When I first started throwing it that way it was more of a curveball. I was trying to get on top of it more to get more depth — something to get under the barrel. It was 83-84, but I was manipulating my arm slot to get up and over it. Now I’m staying closer to what my natural arm slot is, and taking my hand to my left hip, as opposed to kind of going straight down and getting to the middle of my body. I’m trying to create a little more side-to-side break on it that way.
“I have a three-quarter arm slot, and when I was throwing more of my curveball, my slot would get a little higher. Now, getting it to my hip on my release is giving me the sideways break I’m looking for.”
Laurila: Was more horizontal break the primarily goal, or was it more about staying in the same arm slot?
Walden: “It was more to create my fastball look. If something is coming out of a different window, the hitters are going to see that. They’re going to be able to read slider out of the hand. Now I’m more in the arm slot of my sinker and my cutter, while still creating some horizontal break.”
Laurila: You stopped throwing a slider for several years before reintroducing it to your arsenal. Why?
Walden: “It kind of just happened. I ended up having Tommy John in 2009. I was throwing it then. I don’t necessarily know that was the cause of me needing Tommy John, but my elbow hurt when I was 14, 15, 16 years old. That’s why I didn’t pitch when I was in high school; not until that last year. I’ve always had elbow issues, from the time I was 12 years old for the most part. It never really hurt, but every time I pitched I’d be a little sore.
“As I got older, I really wanted to focus on having two good pitches. That was my sinker and my cutter. I started with just sinkers arm side, and cutters extension. Then I tried to flip it and go sinkers backdoor, cutters backdoor. I did that for three or four years out of the bullpen. Then I needed to get a breaking ball — something slower — when I was starting. That’s what really got me back into throwing my slider.”
Laurila: Alex Speier wrote in The Boston Globe that you basically went back to the slider out of necessity. Without it your career was in jeopardy.
Walden: “Yes. I mean, I have always been able to get ahead of guys, to be able to pound the zone early. But putting guys away on 0-2 and 1-2 counts was something I really struggled with. This was for many of the years I played in the minor leagues. Having a slider helps everything play better.”
Laurila: Circle back to what you gleaned from talking to Kimbrel. His breaking ball is elite, and thus something other pitchers probably aren’t going to be able to replicate.
Walden: “I actually rarely talked to him. I was new to the big leagues, and I’m also a person who believes in being seen and not heard. But like I said, I watched his live BPs from behind and saw how he was gripping it, and what his arm path was. I was figuring out, ‘OK, this is what he’s trying to do.’ If you go back and look at video, you’ll see that his slider is more horizontal. It’s an easier pitch to control to get ahead in counts, and then later in counts he wants it a little bigger — a bigger sweeper, a little more horizontal to get away from the barrel. I kept watching him, and watching him. I was lucky to be there in the spring of ’17, and the spring of ’18, and the beginning of last season as well. Then I got hurt for about 10 weeks. I had a strain in my arm flexor.
“Having watched more and more of Kimbrel, I was able to process, ‘This is what I’m going to do when I come back.’ And I have a Rapsodo, so this past offseason I was looking at what break I’m getting on certain pitches. I’d throw three or four of them, look at my numbers, and then go, ‘OK, now I want to get more horizontal.’ Being able to look at my numbers really helps me know what I want to do.”
Laurila: When did you buy a Rapsodo?
Walden: “I bought that two offseasons ago. I actually have my own baseball facility [DIB Baseball Academy] back home. We have any academy in Fresno — three of us own it — and a Rapsodo is one thing I really wanted to buy. We could use it to teach kids, and I could obviously use it for my own benefit. That’s really where the game is going, with all of the analytical stuff.”
Laurila: What is the spin rate on your slider?
Walden: “It’s between 2,400 and 2,500 rpm. When I first started throwing it, it was a little bit higher, but I didn’t have as much control over it. I’ve opted for a little more control, a little less spin and break, in order to be able to put it on the side of the plate I want, to be able to better manipulate the depth and horizontal break.”
Laurila: Tell me a little more about your facility back in Fresno.
Walden: “We have kids all the way from age five all the way up to… we have guys who are just graduating college this year.”
Laurila: Are you big on teaching the slider?
Walden: “We don’t really throw a lot of offspeed; not with the younger kids. I did, and I think that’s what a lot of my arm issues stemmed from. I threw a lot sliders, a lot breaking balls, when I was maybe a little too young. I also pitched a lot. That was part of the issue.
“I’m more into mechanics, and being able to throw fastballs in the zone. If you can’t throw a fastball down and away, you can’t pitch. When you can start doing that consistently, then you can start working on cutters and changeups. The slider/breaking ball is pretty much for when you’re 16-17-18 years old. That’s my opinion. I don’t like teaching it to younger kids. I may have a good slider now, but that doesn’t mean they should be throwing one. Not until the right time comes.”
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.