ANAHEIM -- Instead of easing him into the big leagues as a relief pitcher as originally planned, Astros top prospect Hunter Brown will make his Major League debut as a starter when he takes the ball for Monday’s series opener against the Rangers on Labor Day at Minute Maid Park.

Brown, the No. 71-ranked prospect by MLB Pipeline, was added to the Major League roster on Friday and started to get loose in the bullpen in the middle of Friday’s win over the Angels before the Astros opted to use their high-leverage relievers in a close game. Brown’s start will mark the most anticipated debut for an Astros homegrown starter since Lance McCullers Jr. in 2015.

“I wasn’t sure if I was going to get in this weekend or not,” Brown said. “A little bit of concrete information was nice. I was ready to come out of the bullpen this weekend or going forward, or obviously start on Monday.”

Brown dominated the Pacific Coast League this year. He posted a 2.55 ERA, 1.08 WHIP, .186 batting average against and 134 strikeouts in 106 innings in 23 games (14 starts) for Sugar Land. His last outing for the Space Cowboys came on Sunday, when he threw 3 1/3 hitless innings in relief. Brown was informed after that game he would be called up when rosters expanded Sept. 1.

“We had a plan [Friday] night that he may piggyback after Lance, but when [McCullers] went [5 2/3 innings] and the game was so close, we decided not to,” Astros manager Dusty Baker “We were trying to mix up our rotation. [Pitching coach Josh] Miller and I talked about it and didn’t want [Brown] out too long. At the same time, we didn’t want to break up a couple of guys in the rotation. We thought it would be best for him to go Monday.”

Brown can touch 99 mph with his fastball and has a powerful curveball that sits in the low 80s, along with a hard slider that he can throw in the upper 80s. He grew up in suburban Detroit and tried to mimic the mechanics of Justin Verlander, who’s now a teammate in Houston.

“Kind of trying to put that aside right now,” Brown said of the emotion surrounding his debut. “Mostly just because we’re trying to win a World Series, trying to close out the year. I’m trying to be a good member of this team and show the coaching staff and the other guys on the team, too, that I can pitch. I think Monday is going to be a good opportunity to do that.”

Brown admits he gets nervous before every start and expects nothing different on Monday. He said he’s familiar with several players on the Rangers, having faced them in the Pacific Coast League while they were playing for Triple-A Round Rock.

“I’d like to think I have it all figured out, but odds are, I don’t know what those emotions are like when I’m out there,” he said. “I’m going to try take it as they come and do the best I can to focus on my job.”