"I had to scramble a little bit to make sure I made that flight to San Diego," Cain said.
Cain was in the Royals' lineup on Monday night at Petco Park and Jimmy Paredes, who was optioned back to Omaha to clear roster space, played third base for the Storm Chasers on Monday afternoon.
Paredes got into just four games for Kansas City, entering each time as a pinch-runner, since being called up on April 18. He was 0-for-1 at the plate and scored two runs.
Cain played just two games at Omaha, one as designated hitter and the other as center fielder, and was 0-for-7 at the plate.
"No knocks but, hey, I'm ready to go. I'll come out swinging tonight and see what happens," he said.
What happened was that Cain went 4-for-5 with three singles and a double in the 12-inning, 6-5 loss to the Padres. So he was apparently ready.
Cain went on the disabled list on April 16 with a left groin strain. At the time, he was batting .333 (14-for-42). He'd expected to get more Triple-A at-bats to sharpen his timing before getting called back.
"That was the initial plan," manager Ned Yost said. "But this is a big outfield, too, and he was feeling really good. Instead of shagging fly balls for Omaha, we wanted him shagging fly balls for us. It was that simple. So let's get him here."
The timing of the callback seemed good for another reason.
"Especially when we're struggling to score runs," Yost said.
Cain, stymied by three leg injuries in 2012, has worked to change his running style to minimize the chance of pulls and strains. Recently, he noticed he'd lapsed into an old habit of lunging for first base which he'll try to eliminate. For now, everything is fine.
"The groin feels great. I'm running, played the outfield a little bit," Cain said. "Overall, I feel good, my legs feel great."