HOUSTON -- The biggest positive development of the Astros’ 2024 season has been the emergence of right-hander Hunter Brown into a top-of-the-rotation arm, someone you can give the ball to and feel good about your chances.

Brown, in his final home start of the regular season, held the Mariners to one run in six innings in the Astros’ 6-1 loss Monday night at Minute Maid Park, getting outdueled by Seattle’s Bryce Miller. If Brown doesn’t pitch again in the regular season -- he could start this weekend in Cleveland if the Astros still haven’t clinched -- he finished with a 3.49 ERA in 170 innings, while striking out a career-high 179 batters.

The loss postponed what the Astros hoped would be a champagne-filled clubhouse party. They need to beat the Mariners once in the three-game series to win their seventh American League West title in the past eight seasons and will hand the ball to ace Framber Valdez on Tuesday.

“It’s been a long year, you know?” Brown said. “I guess I could say I’m proud of myself from where I looked at myself as a pitcher at the beginning of the year and how I view myself now. I don’t know if my regular season is over. But if it is, we’ll start eyeing the playoffs, but we still have a little bit of work to do here. We’ve got to bring it to these guys and put ourselves in a position to make a run here.”

Miller held the Astros, who are without All-Star slugger Yordan Alvarez in this series due to a sprained right knee, to two hits in seven scoreless innings to keep Seattle’s AL West hopes alive.

“He was almost unhittable today,” Astros second baseman Jose Altuve said.

If the Astros can beat the Mariners on Tuesday or Wednesday, Brown’s next start would come in next week’s AL Wild Card Series. Brown has posted a 1.69 ERA in 10 2/3 innings in seven career playoff games in 2022 and ’23, but he’s never started a postseason game before.

“Man, his development has been phenomenal,” Astros manager Joe Espada said. “Just how he started and where he’s at now and how he’s able to execute and stay calm, navigate really good lineups and throw all his pitches. In any count, he can throw all his pitches. His progress has been really, really good.”

Brown was 0-4 with a 9.78 ERA in his first six starts of the season, mirroring the struggles of an Astros team that was 7-19 out of the gate. He added a sinker to his repertoire on May 5, giving him something to throw inside to right-handed hitters. It opened up his entire arsenal.

Brown went 11-5 with a 2.51 ERA in 147 innings in his final 24 games (23 starts) of the regular season, helping the Astros wipe out a 10-game deficit in the division. He’s come a long way from his April 11 start at Kansas City in which he allowed nine runs and 11 hits and recorded two outs.

“I was really struggling to get any outs and now I feel pretty confident I can handle any lineup in the big leagues,” Brown said. “Simply put, that’s the way to describe it.”

Brown’s emergence is not only a bonus for the Astros this season, but also going forward, Espada said.

“Finding starting pitching like that, it’s really challenging,” he said. “Just knowing that we have a homegrown right-handed pitcher that can do the things that he can do, it puts you in a really good spot for the present and the future.”

Brown and Miller, born six days apart in August 1998, are two of the game’s best up-and-coming arms and went toe-to-toe. Brown’s only blemish came after back-to-back walks to Josh Rojas and Victor Robles in the third, with Cal Raleigh hitting an RBI single to right field.

“I thought, really, if I didn’t lose Rojas and Robles there, they probably finish with zeroes,” Brown said. “I thought my stuff was good today and we just go to come back tomorrow and battle these guys.”

With champagne still on ice, the Astros will send ace lefty Framber Valdez to the mound against Logan Gilbert. The Astros have won 13 of Valdez’s last 15 starts, with the lefty going 9-2 with a 2.04 ERA and 0.99 WHIP in that span.

“We have Framber tomorrow,” Altuve said. “He’s another guy that’s always going to give you a chance to win and we feel confident about our offense. Tomorrow’s another day.”