PHOENIX – Twins pitching prospect David Festa, who has one of the highest strikeout rates in the minor leagues, is set to make his major league debut Thursday against the Arizona Diamondbacks.

Festa, 24, was informed he will be called up and added to the 40-man roster to start Thursday's series finale at Chase Field, the Star Tribune learned. Festa, a righthander, fills the final spot in the Twins' rotation, at least temporarily, after Chris Paddack was placed on the 15-day injured list Tuesday.

The 6-6, 185-pound Festa has posted a 3-2 record and a 3.77 ERA through 14 starts with 87 strikeouts and 24 walks in 59⅔ innings.

"When I saw him, it was guaranteed 10 punchouts," said Twins utility Austin Martin. "Haven't really been able to be around him too much, but from the outings I've seen, he's got the stuff. Every time he goes out, he competes. He takes everything very serious. He's very meticulous with his work. He's got a good pitcher's mentality when he's on the mound, you can kind of feel his presence."

Festa, who did not arrive to the Twins clubhouse before Wednesday's game, started this spring in major league camp, though he didn't pitch in any big-league spring training games. The Verona, N.J., native emerged as arguably the top pitching prospect in the organization after the Twins took him in the 13th round of the 2021 amateur draft. He represented the Twins at the MLB Futures Game last summer.

He was initially set to play college baseball as an infielder until a late growth spurt put him on the mound in his senior year of high school. He spent three seasons at Seton Hall, and he's continued to gain velocity almost every year in pro ball.

In his last start with the Saints, last Thursday, he yielded six hits and four runs in 5⅔ innings with no walks and six strikeouts. He's had success this year relying on his slider and his changeup to generate swings and misses while his fastball sits around 95-96 mph.

"Every time I've seen him pitch, he's always either striking them out or making them look uncomfortable some other way," Royce Lewis said. "I'm very excited to see him pitch."

The Twins already have an open spot on their 40-man roster.

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Jeffers bouncing back

Ryan Jeffers, who entered Wednesday on a six-game hitting streak, believes he's back to the best offensive version of himself after slumping for about a month.

Jeffers was one of the best offensive catchers in the majors for the first six weeks of the season, then had a 25-game stretch in which he hit .145 with four homers, seven RBI and totaled 29 strikeouts in 83 at-bats.

"Something I've been trying to do really well over the last week is treat every [at-bat] like a spring training day," he said. "Spring training, you're so focused on the process. You're so focused on the plan. 'Hey, did I have a good AB? Did I swing at the right pitches?' Really trying to put onus on that, and on top of that, doing the work and getting back to where I was the first month. I feel like I'm back to that guy again."

Jeffers looks more balanced at the plate, totaling one strikeout across 26 plate appearances during his hitting streak. He hit a game-tying, three-run homer in Tuesday's 5-4 loss — his first homer since May 30 — and he had a scorched lineout for the last out of the game.

What caused his slump?

"It was just a lot of different things," Jeffers said. "I was getting caught between. I wasn't attacking. There was just so much stuff that I was doing really well at the beginning of the year that I just kind of started not doing well."

Etc.

* It's been a hot stretch for Byron Buxton, entering Wednesday with a .346 batting average, eight extra-base hits and 10 RBI in his last 14 games, but he's continued to bat seventh in the Twins lineup. Manager Rocco Baldelli says he's contemplated moving him up in the batting order, but "it's not something that I want to do as soon as a guy starts swinging it good, immediately you have to move him into a different spot in the lineup. I think our lineup has good depth right now."

* Yunior Severino had three hits and two RBI, Brooks Lee homered for the fifth time in his last seven games and the St. Paul Saints won 9-7 Wednesday in a road game against the Iowa Cubs. Edouard Julien drew three walks and scored twice.