AJ Causey was 13 years old when he accepted pitching might not be his future.

He didn’t throw all that hard. He relied on finesse and a trustworthy changeup. He should just try to hit his way through the baseball world instead.

One of Causey’s coaches at Viper Baseball Academy in Huntsville, Alabama, had a different plan — and a plan to be different.

Scrap being like everyone else that throws over the top. Try throwing sidearm and bring the your own look to the mound. Causey accepted it and altered his future.

“I was like, ‘This is a cheat code,’ ” Causey said. “I tried it and I fell in love with it. It almost made pitching like a game to me — almost like wiffle ball.”

Causey (12-3, 3.98 ERA) is Tennessee baseball’s cheat code, creating uncomfortable at-bats and awkward swings with his uncommon arm slot and pitches. He is a unique asset unleashed perfectly in the Vols’ heralded pitching staff as No. 1 Tennessee (53-11) steams into the Knoxville Super Regional starting Friday (3 p.m. ET, ESPN 2) against Evansville (38-24) at Lindsey Nelson Stadium.

How AJ Causey became a sidearm pitcher — and how Wiffle Ball helped

Causey ranks second in age among the four Causey boys. He ranks fourth in Wiffle Ball by his own admission.

VBA coach Andrew Dennis knew Causey dabbled in throwing a Wiffle Ball from different angles. Why not try to do the same with a baseball?

“You can do anything to a Wiffle Ball,” Causey said.

Causey claimed comfort and confidence in Dennis’ plan because of those backyard Wiffle Ball games.

He experimented in the offseason following his 13U travel season with the sidearm slot. He arrived early for training at VBA to master a sidearm sinker. He spent a year working on only on that pitch. He debuted the new look in his 14U season, throwing both sidearm and over-the-top. His confidence buoyed when his velocity rose from the side but remained a part-time sidearmer in high school.

The 6-foot-3, 205-pound Causey gained velocity and touched 92 mph over the top as his frame filled out at Sparkman High School. He scrapped it entirely at Jacksonville State when he noticed hitters waited for him to throw over the top.

“They would put a better swing on it than when I was throwing from the side,” said Causey, who transferred to Tennessee in June 2023.

Causey throws a breaking ball he calls a “sweeping sidearm curveball.” He began working on it after he got the two-seam fastball down. He toyed with an inconsistent splitter. He abandoned it for a changeup, which he has turned into an effective third pitch under Vols pitching coach Frank Anderson.

He has studied the mechanics and physical demands of throwing sidearm. He credits “Building the 95 MPH Body” by Ben Brewster as a pivotal book in his progression. The sidearm slot is predicated on more tilt in the torso and the use of obliques.

Anderson has helped Causey stay back with his upper half, which has improved his control.

“I could almost stick it in (the glove),” Causey said.

AJ Causey unlocked his success by working with mental coaches

Cal Stark had a question for Atlanta Braves pitcher Spencer Strider.

“When did you really see your game start to elevate and what did you do?” the Vols catcher asked Strider, a CAK graduate who spoke to the Vols in the fall.

Strider explained his pitching changed when he grasped the mental side of baseball.

Causey vowed that day to explore the ways his mind could affect his pitching. He met with Dr. Joe Whitney, Tennessee’s director of mental training, and former Vols and major league pitcher Luke Hochevar to dive into a new realm.

“It was mind-blowing just how big that part of the game is,” Causey said.

Causey’s next outing was the Orange and White World Series. He never felt better on the mound — physically or mentally. Whitney and Hochevar became Causey’s “mental coach combo” and weekly meetings are part of his routine to master what he focuses on when he’s on the mound.

Pitching isn’t simply about throwing a strike and trying to throw something a hitter won’t hit, Causey explained. That is pitching out of fear.

He wants to throw elite pitches every single time. He has full confidence he can place pitch after pitch on the corner of the plate. He believes if he puts the pitch where he wants, he will win every pitch.

"When you are pitching where you attack and throw elite pitches, it flips the mindset,” Causey said. "You are not pitching scared. You are pitching on the hunt.”

Causey’s mental makeover led to a huge start to his Vols career but his success halted early in SEC play. He was hammered against Georgia and Auburn. He slipped away from throwing elite pitches and needed to reset his mind again with Whitney and Hochevar.

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The results have been remarkable since the LSU series in mid-April with the emphasis on throwing elite pitches and nothing else.

“That is all I need to think about,” said Causey, whose 12 wins are the most for a Vols pitcher since Hochevar won 15 in 2005.

How AJ Causey became a long relief ace for Tennessee baseball's staff

Northern Kentucky coach Dizzy Peyton laughed when was asked about Causey’s latest polished appearance.

“It looked like he was throwing a wiffle ball to me,” Peyton said. “That thing is pretty funky.”

Causey came to Tennessee hoping to be a starter. He did so for much of the nonconference season and into SEC play. He shifted back to the bullpen but in a long relief role. Causey has piggybacked starter Chris Stamos, who is used as an opener.

“Seeing another pitcher that is more traditional then I come in as a sidearmer, it is such a different look,” Causey said.

Causey was a closer as a freshman at Jacksonville State and a starter as a sophomore. This was a new role, but one he was receptive to seeing how successful the starter-to-Causey pattern was against Texas Tech in February.

He struck out seven in 4.2 scoreless innings behind AJ Russell in that game. He has been paired with Stamos since mid-April, following the over-the-top left hander with a big curve.

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Causey has a 2.84 ERA in his past eight outings — all out of the bullpen. He has struck out 58 in 44⅓ innings, allowing 14 runs on 40 hits and nine walks. He has thrown at least five innings in six of the eight appearances and tallied at least seven strikeouts in seven.

He struck out nine in 6⅔ innings against Northern Kentucky, both his bests out of the bullpen.

The system works and so does Causey’s stuff. He prides himself on being different — both in how he throws and the role he fills.

“It’s all pitching,” said Causey.

So is his future.

Mike Wilson covers University of Tennessee athletics. Email him at michael.wilson@knoxnews.com and follow him on Twitter @ByMikeWilson. If you enjoy Mike’s coverage, consider a digital subscription that will allow you access to all of it.

This article originally appeared on Knoxville News Sentinel: How AJ Causey became Tennessee baseball's ace relief pitcher