HOUSTON -- The good news for the Astros on Tuesday night is they didn’t have a starting pitcher go down with an injury. That’s little consolation for rookie right-hander Hunter Brown, who lamented a career-high five walks in 4 1/3 innings and the first loss of his young career.

Brown, who had thrown seven innings without allowing an earned run in three of his previous four starts, gave up two runs and four hits while striking out four batters in the Astros’ 2-0 loss to the Giants at Minute Maid Park. It was a 31-pitch fourth inning, in which Brown walked three batters, when his lack of control started to betray him.

“I think everything tonight was not good,” Brown said. “I was leaving a lot of balls over the middle of the plate or really not giving them a chance to do what I want with some weak contact. Honestly, got bailed out by the defense -- [left-fielder Corey Julks] made a nice play, [catcher Yainer Diaz] threw somebody out, [second baseman Mauricio Dubón] made a nice play at second base. It probably could have been worse, but [my] teammates helped me out tonight.”

The Astros were shut out for the first time in 2023, with Giants starter Anthony DeSclafani throwing eight scoreless innings. Diaz had two of the Astros’ three hits and threw out a pair of runners trying to steal. He’s worked with Brown in each of his last five starts and knows his stuff well from their time together in Triple-A.

“Obviously, he’s not a machine, so maybe today he wasn’t executing some of the pitches as consistently as he’s used to,” Diaz said. “The zone is a little bit [tight] tonight. He was good with most of his pitches and trying to stay aggressive with them.”

Brown relied mostly on his three-pitch mix of a curveball, fastball and slider against a Giants lineup that had six left-handed hitters. He had trouble spotting his breaking ball at times, throwing strikes on 59 percent of his curveballs and sliders combined.

“He couldn't find his breaking ball,” Astros manager Dusty Baker said. “He threw a lot of near strikes. They looked close from where we were. Very close. He wasn’t as sharp as he was [in] his last start, but like I said, he was very close. He was throwing the ball well.”

After giving up a run in the first, Brown retired seven consecutive batters before things went awry in the fourth inning. Seven of the final 10 batters Brown faced reached base, including the five walks. His pitching line could have been much worse had reliever Matt Gage -- called up from Triple-A earlier in the day -- not escaped a bases-loaded jam to end the fourth.

“Five walks is definitely not what you're shooting for,” Brown said. “Just couldn't find it.”

Diaz, starting for the first time since he caught Brown on April 26, has gone 8-for-23 (.348) since starting the season hitless in his first eight at-bats. He threw out Thairo Estrada at second base trying to steal in the fourth on an 86.5-mph throw and Austin Slater at second in the eighth on an 85.9-mph throw, giving him five caught-stealings in 10 attempts this year.

“As a rookie, when I first came up, I wanted to be overly aggressive just to show I belonged in the lineup every single day, but since then I’ve got a chance to speak to the hitting coaches, and [I] have been going up there more calmly at the plate. That’s why we’ve been seeing the different results,” Diaz said of his offense.

Considering the Astros lost José Urquidy to a shoulder injury Sunday and Luis Garcia to an elbow injury Monday, the Astros will need Brown to bounce back in his next start on the road and provide a lift to a rotation that has three starters on the injured list -- Urquidy, Garcia and Lance McCullers Jr.

“I’m just going to trust the process and take my throwing program and my next bullpen and be excited to go out there again when I get another opportunity,” Brown said.