OAKLAND -- Luis Medina was on the brink of transitioning to a bullpen role in the Minors when Mason Miller’s UCL sprain opened a spot in the A’s starting rotation. Called up to fill that void, Medina is making a push to solidify himself as a starter at the highest level.

Making his third Major League start in Wednesday’s 5-3 loss to the D-backs at the Coliseum, Medina delivered his second consecutive quality outing, allowing three runs on three hits and two walks with six strikeouts over six innings. It was the second consecutive quality outing turned in by Oakland’s No. 18 prospect, following up on his solid outing against the Rangers over the weekend.

“Medina did great,” said A’s manager Mark Kotsay. “Overall, it was a quality start by every measure. He gave us a chance to win the game. He’s done it twice now in back-to-back starts.”

The long ball is Medina’s main kryptonite so far as a big leaguer. The right-hander's three runs allowed came on Christian Walker’s solo shot in the second and Corbin Caroll’s two-run blast in the sixth, bringing his home runs allowed total to five in 17 innings pitched.

Throughout his pro career, struggles with command were the main knock on Medina, which led to most scouts projecting him as a future reliever. To this point, however, control has not been an issue. Against Arizona, Medina threw 62 of his 96 pitches for strikes, and his second walk did not come until the sixth.

“He’s not afraid to throw inside,” Kotsay said of Medina. “You have to like his mound presence. He’s mixing his pitches well. … He knows how to pitch. It’s a great sign to have a young arm out here doing this well in his first couple of starts.”

On Wednesday, Medina got the job done even without his usual blazing fastball, which typically flirts with triple digits on the radar gun. Averaging 94.7 mph with his heater -- 1.2 mph below his season average -- Medina still managed to miss barrels, as D-backs hitters averaged an exit velocity of 84 mph on their 10 fastballs hit in play against him.

Instead of just overpowering hitters, Medina kept them off-balance with a high variance of speeds on the fastball, with speeds ranging from 91.6 mph to 97.5 mph.

“He’s a pitcher,” said A’s right fielder Ramón Laureano, who launched a game-tying three-run homer in the seventh. “He didn’t have his fastball even close to his normal velo and look what he did. Three hits allowed. He’s a gamer and he’s a tough guy. I like him a lot.”

With Miller expected to be sidelined for the foreseeable future, Medina has earned the opportunity to try and stick as a Major League starter. So far, the A’s have been pleased with the results.

“These starts that we’ve seen, the stuff is there,” Kotsay said of Medina. “He’s got multiple weapons to pitch with, which is needed as a starter. The mentality is great. The work ethic is there. Now it’s about going out and performing, which he’s done.”

With three big league starts under his belt, Medina has shown promise. Touted with the ceiling of a frontline starter, the chance to prove that will continue to come in what is a rebuilding season for the A’s as they seek to identify players who can help them beyond 2023. In his mind, the best is still yet to come.

“This isn’t the time to feel comfortable yet,” Medina said in Spanish. “I have to keep working hard to keep giving the best of myself.”