The Athletics optioned right-hander Luis Morales to Triple-A Las Vegas on Tuesday, a day after he issued a career-high six walks against the Houston Astros. Manager Mark Kotsay cited the 23-year-old’s lack of command and confidence as reasons for the demotion.

Morales, who made the opening day roster despite walking 14 batters in 19 spring training innings, went 0-2 with a 12.27 ERA in two starts. He allowed three home runs to Toronto on March 29 and gave up eight hits and six walks in his last start Saturday.

“We talked a lot about performance and being something that we were really evaluating,” Kotsay said before Tuesday’s series opener against the New York Yankees. “These last two games, command has been a big issue for Luis.”

Kotsay noted that the team had hoped Morales could fix mechanical issues at the major league level but that the struggles became too pronounced. “We’re going back to spring training — you don’t look at performance in spring training — but you look at the quality of the pitch-making and he didn’t have a great spring,” Kotsay said. “We felt like he could make the adjustment to being able to fix some mechanical things that he needs to work through.”

Morales signed with the Athletics in January 2023 and had a 3.14 ERA over 48 2/3 innings last season, with 18 walks. The A’s, who are scheduled to move to Las Vegas in 2028, have issued 58 walks in nine games this season, second-most in the majors.

Morales was slated to start this weekend against the New York Mets. Kotsay did not announce a replacement. To fill the roster spot, the Athletics purchased the contract of reliever Joel Kuhnel from Las Vegas. Kuhnel, who did not pitch in the majors last season, has a 5.86 ERA in 82 career appearances with Cincinnati, Houston and Tampa Bay.

“Just the lack of confidence overall, too, you could see it the last start,” Kotsay said. “So, I think it’s a good reset for Luis. My expectation is he goes down and he gains his confidence back and he’ll be back with us at some point.”