PEORIA, Ariz. -- This is the new world of Major League Baseball. Moments after throwing their first bullpen sessions of the spring at Mariners camp, veterans Wade LeBlanc and Cory Gearrin huddled to study the spin rate data on a hand-held Rapsodo machine.
Feedback on the latest analytics is now instantly available in the Mariners' bullpens at the Peoria Sports Complex, where cameras catch every throw using a radar system that spits out information that can help pitchers understand how much movement, velocity and spin they're getting on different pitches.
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TrackMan and Rapsodo devices are the new norm in training for pitchers and the Mariners are among the teams fully embracing the technology, having added coaches and staff who can help the athletes absorb as much of the data as they want to use.
Rather than rely strictly on a coach telling them it appears their stride is too far down the mound, or that their release point has changed, pitchers now can study images showing precisely where their landing foot is coming down or exactly where the ball leaves their hand on different pitches, as well as how much and where each pitch is moving as it approaches the plate.
LeBlanc, a 34-year-old who has pitched for seven MLB teams in a 10-year career, welcomes the technology as another tool that can help refine his craft.
"It's crazy. If you'd have asked me two years ago, I'd have said, 'I'm not using that stuff,'" he said with a laugh. "But I'm an average pitcher. I want to be above average. So why wouldn't I use something that we have here that can help?"
LeBlanc now uses Rapsodo readouts to study the horizontal and vertical movement on his different pitches, with the goal to make each look as close to the same until the last second in order to reduce hitters' ability to recognize and react.

"It reads the break from the catcher's viewpoint, from up top and from the third-base coaching box," he said. "You can see the plane of the pitch and how long it holds its plane. That's mainly what I look at. I want to make sure the movement is as late as possible. Some guys get into the spin. I don't really know what that means, but some guys look for that. And some guys obviously look for the velo, which I don't want to see.
"But let's say I'm throwing a cutter, a fastball and a changeup. I can take those three viewpoints of the break and overlay them and make sure they all look the same as long as possible. Because that's what is going to make a guy like me effective. You want each pitch coming out of the same spot, release point and look the same as long as possible, hopefully up to 50 feet before they start moving."
Justin Dunn, Seattle's No. 3 ranked prospect per MLB Pipeline, says the technology allows him to see exactly how he can get different movement on pitches and takes the guesswork out of adjustments.
"Let's say I'm working on a changeup where I'm trying to kill velocity," said the 23-year-old right-hander acquired from the Mets this past offseason. "I say, 'All right, if I move my finger here, I get the break and sink and velocity off, but if I do this, I get even more.' It's good for instant feedback on manipulating the baseball, while working at the same time."
In every bullpen session, pitchers throw with a camera at their back and a black box behind the catcher. The radar recording is transmitted to a tablet that coaches can watch as the pitchers are throwing and the players can view as soon as they're done.
"The technology allows for more objective teaching," said manager Scott Servais. "The numbers don't lie. I'm not going to say I'm a guru on it all and know how it all works, but I certainly see the value. And as I continue to learn and understand what we're doing to help our players along, I think it's great.
"I do think we need to be careful we don't overload. There's a fine line there. That's one thing I really impressed upon our coaching staff: We're building. We're establishing a foundation. This is how we're going to do things. It's a process and it's slow and you have to be patient with it."
Many players now train at offseason facilities using the technology. Others are just being exposed. Some embrace it, some ignore it. But the game is changing and players and coaches are learning together along the way.

Gearrin, a 32-year-old reliever who signed as a free agent this winter, said he'd be foolish not to take advantage of any information that might give him an edge.
"I think as players, we're still learning how to use it," he said. "And organizations are still learning the best ways to utilize it. But we've seen around the league that teams using data and technology well -- and figuring out how to get it into players' hands and really be able to weaponize it for guys -- are seeing positive results."
Like anything new, there will be a learning curve. But for a pitcher trying to improve his curve, knowledge is power, especially when it involves spin rates. Yusei Kikuchi, who is coming over from Japan, said he looks at the "spin axis" of his pitches. Others study how their stride length affects their velocity or point of release.
For the Mariners, the goal for now is to provide the information and coaches who can help translate it, led by new pitching coach Paul Davis, director of pitching development Brian DeLunas and bullpen coach Jim Brower, then let the players decide how much of that data works for them without overloading their systems.
"I engaged in guys about, 'Hey, what can we do here?' and they were all about having that conversation," Gearrin said. "But it's all individual. Some guys work better with no information, they just want to go compete. And some guys are very analytical and want all the information you can give them. And most guys fall somewhere in the middle."