Mariners GM Jerry Dipoto: Boost in velocity wasn’t primary reason for changing James Paxton’s arm slot

The Mariners worked with left-handed starter James Paxton on his mechanics after spring training, adjusting his arm slot from over the top to more of a three-quarters approach. It’s worked wonders, as he’s been sitting in the high 90s with his fastball and even reaching triple digits since being called up from Triple-A on June 1.

Funny thing is, the Mariners were just trying to get more action on Paxton’s pitches by changing his arm slot and weren’t really expecting a dramatic increase on his fastball. Yes, much like the (sadly fictional) tale of 12-year-old Cubs ace Henry Rowengartner, Paxton’s boost in velocity to fireballer status was more of a happy accident than the intended outcome.

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“We were trying to get him into a slot where he could manipulate the ball, create better movement and more consistency with his breaking ball, and the unexpected result was that it resulted in a significant velocity jump,” Mariners general manager Jerry Dipoto said during his weekly interview with “Danny, Dave and Moore” on 710 ESPN Seattle. “We sent him to Tacoma (after spring training), and he went through a very slow and subtle delivery change. In the effort to make sure we weren’t doing anything to risk future health, he worked with Lance Painter and he worked with Rick Waits and our staff to try to lower his arm slot. Not always the easiest thing to do for a pitcher, because it feels right the way you’re doing it. He was so far over the top in spring training and even coming out of the fall league last year that he was not able to manipulate the baseball very well.”

He’s doing plenty more than manipulating the ball better. Paxton, who Dipoto said averaged about 94 mph on his fastball in previous years and 92 in spring training, has been sitting in the 97-98 range.

“It’s kind of incredible and I wish I knew the results were going to be quite that dramatic in terms of velocity. Maybe we try it with everybody…” Dipoto said somewhat jokingly.

The big velocity numbers are nice, but the best part about the new arm slot for the Mariners and Paxton is that it has translated on the mound. After a rough season debut in San Diego, Paxton has reeled off three straight quality starts, including a six-inning, five-strikeout outing in Thursday’s 6-4 win over Tampa Bay.

While there is certainly credit worth giving to the Mariners’ minor-league staff for Paxton’s turnaround, Dipoto was sure to praise the 27-year-old Canadian for embracing the change.

“In James’ case, kudos to him for being open and receptive to the changes. It’s really worked for him and as I said to him … whatever place he’s in right now, stay there. It’s just been fantastic.”

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