Instead, Mikolas received the news he was headed to the Major Leagues.
The Padres selected Mikolas from Double-A San Antonio on Saturday to replace closer Huston Street, who went on the 15-day disabled list for a strained right lat. To make room for Mikolas on the 40-man roster, the Padres moved infielder Logan Forsythe to the 60-day disabled list.
Mikolas, who made his debut in the ninth inning of Saturday night's 4-1 loss, was 1-1 with a 2.92 ERA in Double-A. He allowed a solo homer to the first batter he faced, Giancarlo Stanton. He also struck out two and walked one.
"This spring, he threw the ball well," San Diego manager Bud Black said. "I think that continued on there in San Antonio. Of all the guys that we looked at, he was the guy that our Minor League people said, 'He's the guy.'"
Mikolas caught a flight out of San Antonio and arrived at Petco Park shortly before 2 p.m., roughly 3 1/2 hours before the team's first pitch against the Marlins.
"I had a little time to get ready," Mikolas said. "I had a small bag packed for our trip to Corpus [for a Double-A game]. I had to unpack and pack my big bag."
Mikolas spent much of Spring Training with the big league team, and he's been teammates with some of the younger players.
"It's easier knowing the guys a little bit so you don't just show up and you don't know anybody at all," Mikolas said. "There are a lot of young guys up here, which makes it a little easier to make the transition."