When the Orioles looked ahead to the 2021 rotation, every potential version was going to come with Dean Kremer in it, whether he dominated Wednesday or not. Now the O’s are hoping that when the calendar does turn, Kremer considers Wednesday just a distant memory.

That’s because the rookie right-hander completed his brief 2020 campaign by taking the brunt of Baltimore’s 9-1 thumping at the hands of the Red Sox at Fenway Park. Kremer surrendered seven earned runs over 2 2/3 innings in what was the antithesis of his first three starts, ballooning his ERA from 1.69 to 4.82 in the process. Baltimore believes it is just a blip on the path to development for its No. 10 prospect.

• Box score

“I think I just left too many balls, deeper in counts, center cut,” said Kremer. “I’m pretty happy as a whole. Three of [my starts] went well, and tonight was what it was. I am pretty happy with how I got to dip my toe in the water, and I’m excited for next year.”

Separating Kremer from that is a winter over which he said he’d focus on adding velocity and sharpening his four-pitch mix, with an eye toward building on the promise he showed in his first three MLB outings. Kremer held the Yankees (twice) and Rays to three runs across 16 innings in those games before Wednesday’s blowup.

The trouble came quickly. Kremer allowed a leadoff double and two early runs on RBI singles from Jackie Bradley Jr. and Kevin Plawecki. He never made it out of what became a six-run third inning, giving up run-scoring doubles to J.D. Martinez and Michael Chavis, and an RBI triple to Plawecki. Kremer also dealt with a cut under the nail on his right pointer finger during that frame; Branden Kline let two additional runs score after Kremer was removed.

• Evan Phillips hits IL; elbow prognosis positive

The seven earned runs allowed by Kremer were the most by an O’s rookie since Yefry Ramirez against the Indians on Aug. 19, 2018. The result was Baltimore’s 12th loss in 15 games, after its lagging offense was held to Austin Hays’ solo homer against Nathan Eovaldi and two relievers. The Orioles have scored 23 combined runs in those losses, and are a season-low 23-33 with four games to play.

“I feel like we should be ending the year a little stronger,” manager Brandon Hyde said. “We haven’t swung the bats well the last couple weeks.”

The flip side was the four innings of one-run ball strung together by Bruce Zimmermann, who struck out five in mop-up duty in his second big league appearance. Both rookies, acquired in trades during the selloff of July 2018, figure to factor heavily into the Orioles' '21 plans.

As it stands, the rotation for next season seems mostly set with John Means, Alex Cobb, Keegan Akin and Kremer, with Jorge López and Zimmermann probably battling in spring for the final spot. How quickly they’re joined by prospects like Michael Baummann, Zac Lowther and potentially DL Hall remains to be seen, and hinges on a variety of factors that are largely unknowable at the moment.

But for an organization finishing its third rebuilding season and preparing for some serious 40-man roster churning this fall, glimpses of those long-term goals are becoming more common. And this nucleus of young arms, along with the emergence of Ryan Mountcastle (three hits Wednesday), Hays and others are reasons why. As recently as Opening Day 2019, the O’s rotation featured exactly zero pitchers in their long-term plans. That number could be four by Opening Day 2021, with more on the way.

“All of those guys I think have had periods of throwing the ball well, and I’m looking forward to next year with those guys,” Hyde said. “I’m excited about Dean. I think Dean has big upside. Keegan and Zim also. I think these guys have big upsides, and this has been valuable experience for them this year, getting some starts under their belts and taking it forward into next year now that they’ve gotten a taste of the big leagues.”