SAN DIEGO -- Walker Lockett's first stint in the big leagues was a short one. If Jose Castillo pitches like he did Saturday night, his stay could last quite a bit longer.
The Padres optioned Lockett to Triple-A El Paso on Saturday, a day after the 24-year-old right-hander made his big league debut. They called up lefty reliever Castillo in his place, and he put forth a dominant debut.
Called upon in the eighth inning of an 8-2 Padres victory, Castillo struck out the heart of the Reds lineup in order -- Joey Votto, Eugenio Suarez and Adam Duvall.
"I came in with the mentality of not really thinking about names, not really thinking about who I was facing, and just treating everyone as another hitter," Castillo said. "Luckily I was able to get those results."

Castillo became just the third Padre in history to strike out each of the first three hitters he faced, joining Jeremy Fikac (2001) and Tommy Layne (2012). Having pitched Friday for El Paso, Castillo will get the day off Sunday, manager Andy Green said. He could use the rest. Castillo learned of his impending callup with a 2 a.m. phone call.
"With the time difference, it was 5 o'clock in the morning in Venezuela," Castillo said. "So I called [my family] right away and woke them up. It was really emotional."
It wasn't the first time Castillo pitched in a dramatic setting at Petco Park. During the 2017 World Baseball Classic, he entered a tight game between Venezuela and the United States and proceeded to strike out Christian Yelich and Nolan Arenado.

"You could see the stuff really quickly, how real it is," Green said. "I remember watching him punch out Yelich and Arenado last year -- those guys are all right, too."
Castillo, 22, was part of the deal that brought William Myers to San Diego in 2014. In 19 appearances between Double-A and Triple-A this season, he has a 2.31 ERA with 35 strikeouts and nine walks over 23 1/3 innings. Since his promotion to El Paso, he has a 1.08 ERA in seven appearances.
"He's a guy we've wanted to look at," Green said. "He's going to give us an opportunity to protect our bullpen arms and get out here and pitch. He can turn that opportunity into whatever he makes of it."

Lockett, meanwhile, returns to El Paso with one big league start under his belt. He allowed four runs over 3 2/3 innings on four hits and an uncharacteristic five walks. Lockett hadn't walked five hitters at any level since August 2015.
"For Lockett, it's go down, get back to work, get back to attacking the strike zone, and when the opportunity presents itself again, he could have another chance," Green said.