SAN DIEGO — One of the hottest hitters in the American League is an Orioles rookie who made his MLB debut in August. And, no, it’s neither Samuel Basallo nor Dylan Beavers, the heralded prospects who arrived last month.

It’s Jeremiah Jackson, a beneficiary of Baltimore’s late-July Trade Deadline fire sale who played his first big league game on Aug. 1 at Wrigley Field. The 25-year-old — who had never played above Double-A entering 2025 — proceeded to hit .323 with an .828 OPS over 26 games last month, starting nearly every day.

On Monday, the calendar turned to September and Jackson turned it up another notch.

Jackson collected three more hits and homered in the Orioles’ 4-3 win over the Padres at Petco Park, scoring the winning run on Beavers’ two-out single in the seventh inning. It marked the second three-hit game for Jackson, who tallied a trio for the first time on Aug. 17 in Houston.

With a 12-game hitting streak — the longest active streak in the Majors — Jackson’s average is up to .337 (33-for-98).

“Professionally, this is the best I’ve felt,” said Jackson, a second-round Draft pick of the Angels in 2018 and a former prospect who signed a Minor League deal with Baltimore last Nov. 25. “The mechanics are there. I think the main part is just competing in the box and not trying to do too much and just try to do my job and help the team win.”

Jackson’s fifth-inning solo home run off Padres reliever Adrian Morejon put him in an exclusive group for 2025. Jackson became only the second player to take the All-Star left-hander deep this season, joining Mariners slugger Cal Raleigh, who hit one of his MLB-high 50 home runs off Morejon on May 17.

Morejon left a first-pitch slider over the middle of the plate, and Jackson jolted the offering a Statcast-projected 426 feet to straightaway center field for his third MLB homer.

“Just had a plan, trying to see something in the heart of the zone, just tried to be aggressive early and if he made a mistake, just try to hit that pitch, and that’s kind of what happened,” Jackson said. “I was able to get a good swing off.”

Conider interim manager Tony Mansolino among the many wowed by the feat.

Basallo (ranked by MLB Pipeline as the O’s No. 1 prospect and overall No. 8) and Beavers (O’s No. 3) have impressed, as well. The 21-year-old Basallo began September with a two-double, two-RBI performance that boosted his RBI total to eight through 13 games. The 24-year-old Beavers is hitting .333 (16-for-48) through 15 games after going 2-for-4 vs. San Diego.

But Jackson has unexpectedly stolen the show after turning a strong 40-game showing at Triple-A Norfolk (a .377/.400/.673 slash line with 11 home runs) into his first big league opportunity. He’s even making a strong case to serve as a utility man for Baltimore in 2026, showing improved defense in right field and an ability to handle third base.

Jackson has played more games in right field in the big leagues (20) than he did during his seven-year Minor League career (seven). He struggled initially — which included dropping a routine fly ball during his first defensive start on Aug. 2 at Wrigley — but he has become more reliable, making four plays with ease on Monday.

“It’s been a lot of work,” Jackson said. “Got here and got put in right from the beginning. So now I feel a lot more comfortable, and I think I’ve gotten a lot better. A lot of that just has to do with a lot of hard work and trying to get used to it.”

If Jackson becomes a long-term big league contributor, though, it will be because of his bat — a tool that impressed both Basallo and Beavers when they were all Triple-A teammates during June and July.

When Basallo was in Double-A last year, he played against Jackson, who was with Double-A Binghamton in the Mets’ system. Basallo can easily see the progression from then to now.

“He’s been impressive,” Basallo said. “To see the changes he made this year and see how he’s doing right now, it’s just good for him. I’m happy for him. What he’s doing here on the team, he’s been helping the team more than anybody here.”