Just two weeks after learning that he was being moved to the bullpen for the first time in his professional career, Diamondbacks right-hander Drey Jameson is now re-acclimating to being a starter.

The change came as a result of Zach Davies straining his left oblique in his start on Saturday. The Diamondbacks had several options to choose from to take his place, and they ultimately chose to move Jameson — who was a reliever for all of 10 days — back to being a starter.

While he has always viewed himself as a starter in the long term, Jameson initially had mixed feelings about leaving his bullpen job so soon.

“I was kind of pumped and bummed at the same time, honestly,” Jameson said. “I did enjoy the ‘pen. But ultimately, I want to be a starter. So it was a relief and a chance for me to get back in that role and make a point … that I think I could stay in the starting role and help this team win some games.”

Jameson was effective in his brief stint as a reliever, tallying a 2.16 ERA, 1.20 WHIP and .172/.294/.414 opponent slash line in 8 1/3 innings. He pitched in three games, all of which his team won in no small part because of his contributions.

In every close game, Jameson hoped that his name would be called.

“It’s just the adrenaline rush,” he said. “You could be up three days in a row. Even though if you don’t get in the game, there’s that adrenaline the whole game of like, ‘Am I going in? Am I going in? Am I going in?’

“Now, it’s, like, you know exactly when you’re throwing obviously, and that’s nice, because … you do your preparation all the way up until your start, and you know exactly what day, what time you’re going to be throwing. But yeah, I mean, it’s got its ups and downs in both, now that I’ve done both. But I’m stoked to be back in the starting rotation.”

Jameson made his big-league debut last year on Sep. 15 and made a total of four starts. He went 3-0 with a 1.48 ERA, 1.11 WHIP, 24 strikeouts and seven walks in 24.1 innings.

What began as a four-man race for the D-backs’ fifth starter spot in spring training ultimately ended in a duel between Jameson and his roommate while in the minors, Ryne Nelson. Nelson ultimately won that battle. Jameson made the team as a reliever, a role that ultimately proved to be short-lived.

D-backs manager Torey Lovullo said that he and his front office correspondents struggled with the decision to move Jameson out of his bullpen role, a job that he not only succeeded in, but embraced wholeheartedly.

“We’ve had great discussions,” Lovullo said, “and several unbelievable points were made. He can impact the game four times a week versus once every five days [in the bullpen]. But starting pitching sets the tone, and he’s very gifted.

“That’s where he wants to be, and he deserves opportunity.”

Jameson’s three bullpen appearances had gotten progressively shorter. In his season debut on March 31, he threw 66 pitches. In his next appearance on April 4, he threw 38 pitches. In his most recent appearance on April 7, he threw just 26 pitches.

By all indications, Jameson was on his way from being a fully stretched out long reliever to taking on the role of a more traditional reliever who would consistently pitch in pivotal, late-game situations.

Before Davies’ injury on Saturday, Lovullo said in his pregame presser that Jameson could still be stretched out should a need arise. After the game, Lovullo acknowledged that the window for converting Jameson back to a starter was “tight,” given how much his pitch counts had already been cut back.

Back in January, Diamondbacks general manager Mike Hazen expressed concern about the possibility of using one of his young starting pitchers, such as Jameson, in a bullpen role to start the year.

“If you do,” he said, “there’s really no going back in the other direction, or you’re increasing the risk of injury to the player, unless you’re able to completely back him down, send him down for a month or a month and a half and build him all the way back up.”

Despite that, the Diamondbacks believe that it is still early enough in the season that Jameson can be safely built back up to a starter’s workload. Jameson himself is not concerned about the sudden ramp-up having any adverse effects.

“I don’t think that’s a thing,” Jameson said. “I was already worked up, and I was going out there throwing 26 pitches and then, the next day, I felt perfectly fine to where I could keep throwing. So, my arm is built up. My body’s built up for it. And I think a workload of, you know, four or five innings, six innings is perfectly fine.”

Jameson has relied heavily on his slider in his appearances out of the bullpen, throwing it 37.7 percent of the time compared to a 30.8 percent usage rate for his sinker and 28.5 percent for his four-seam fastball. Last year as a starter, Jameson threw his four-seam fastball more than any other pitch at 34.4 percent, with his sinker and slider coming in at 27.9 percent and 24.9 percent, respectively.

As he enters the starting rotation, he doesn’t expect his arsenal to change much from what he’s been doing, but he did say that game planning will be that much more important now that he could see hitters three or four times in an outing rather than just once or twice.

Jameson is set to make his first start of the 2023 season on Wednesday against the Milwaukee Brewers. He threw a bullpen on Monday and, as of that afternoon, was unsure what his pitch count limit would be in his first outing. Suffice it to say that it will likely take two or three starts for Jameson to become fully built up.

Moving forward, the 25-year-old has “no idea” how long he’ll be in the starting role. When Davies returns, he could move back to the bullpen. Alternatively, maybe he is good enough as a starter that the D-backs feel like they cannot do with out him. Maybe another injury arises, and they need him to start no matter what. Whatever happens, Jameson is hoping that he can make the most of the opportunity.

“I want to be in the big leagues winning ball games,” he said. “So, if it’s Davies comes back and I go back to the pen, so be it. Because it’s your first year, you’re learning. And at the end of the day, next year, if I do go back to the ‘pen … they’re going to hopefully give me a chance to start again, and then I can prove myself then.

“I think, ultimately, that this is a huge, huge time for me as a starting pitcher to prove myself.”

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