When former A’s No. 1 prospect Nick Kurtz delivered an RBI single in his first Major League Baseball at-bat on April 23, he was just getting started.

Now, less than two months and exactly 130 at-bats later, the first baseman is no longer a prospect, per MLB’s eligibility rules. After 130 at-bats, a player loses prospect status and is considered a rookie.

That rookie has cemented himself as a rising star, batting cleanup while blasting his 10th home run Friday night against the Cleveland Guardians.

“He’s definitely earned that opportunity. He’s swinging a really good bat right now,” A’s manager Mark Kotsay said pregame. “It’s his opportunity.”

Kurtz mostly hit between the fifth and seventh spots in the order before Friday, but had most recently hit fourth after No. 2 hitter and fellow rookie phenom Jacob Wilson had to take a day off June 10.

Late-game hero

Kotsay’s decision comes while the 22-year-old is in the midst of a tear where he has homered in five of the team’s past six games, including walk-off no-doubters in both Monday and Thursday’s matchups with the Houston Astros.

The former top prospect’s shot on Thursday not only graduated him from prospect status and delivered a 6-4 win, but also tagged star closer Josh Hader, who is pitching to a 1.67 ERA with 18 saves this season, with his first loss of the year.

“I wish I could hit the ball that hard,” Kotsay said in a postgame press conference, per MLB.com. “When he barrels the baseball, it comes off with some serious exit velo. He’s a big guy, but he uses leverage. It’s fun to watch how far they go.”

Kurtz’s homer on Thursday was a 105-mph, 416-foot bomb, but even that was outclassed by the nearly 112-mph moon shot that gave the Astros the 3-1 loss on Monday.

Four of the past five homers have come in the ninth inning or later for Kurtz, who earned comparisons to Hall of Fame sluggers Frank Thomas and Jim Thome from his manager thanks to his late-game heroics.

“For some reason, seventh inning on, I feel more comfortable in the box,” Kurtz said, according to MLB.com. “Maybe it’s just, after seeing a bunch of pitches that day, I start to feel really good. That’s just kind of the way it’s going right now, so I’m just trying to keep it going.”

Rivaling fellow rookie star

With his home run on Thursday, Kurtz became the youngest player to hit two walk-off home runs in the same series, per the Elias Sports Bureau, and is only the second player at 22 or younger to hit two walk-off dingers in the same month. The other was Hall of Famer Eddie Murray.

Friday’s four-bagger was Kurtz’s 10th of the season, tying him with the Miami Marlins’ Agustin Ramirez for the most among rookies across MLB.

Kurtz’s teammate Jacob Wilson leads the A’s in wins above replacement by nearly a point at 2.5, is the current runaway favorite to win American League Rookie of the Year per a Tuesday MLB.com poll, the first baseman needed just 37 games to hit his ninth dinger of the year. Wilson, who was tied entering Friday with New York Yankees star Aaron Judge for most hits in the MLB, has played 71 games this year.

The A’s ended up splitting the series with the Astros after losing the middle two games, despite a three-hit performance from Kurtz on Wednesday.