The 22-year-old hit his third postseason homer to help Chattanooga to the Southern League title with a 4-0 win over Biloxi on Monday and was told by Double-A manager Doug Mientkiewicz he was getting the call to the big leagues.
"I was speechless," said Kepler, who joined the Twins on Tuesday. "I was about to cry. I don't cry much but I was almost tearing up. I was able to celebrate with my team last night and it was amazing."
The left-handed-hitting Kepler ranks as the No. 6 prospect in the Twins' system and No. 99 in the game by MLBPipeline.com, thanks to a breakout season at Chattanooga in which he hit .322/.416/.531 with nine homers, 32 doubles, 13 triples and 18 stolen bases in 112 regular-season games.
The 6-foot-4 Kepler, who saw time in all three outfield spots and at first base, was named the Southern League's Most Valuable Player.
"It starts with confidence," Kepler said. "It made me see the ball better. Mechanically, I worked in a leg kick. Every day I just came out with the same mindset to stay positive even if I went 0-for-4 or 0-for-6."
Kepler is a career .281/.362/.445 hitter in 427 games in the Minors. He said he is active in trying to make baseball more popular in Germany such as holding baseball clinics in his hometown of Berlin.
"It's big," Kepler said. "Baseball is on the come up in Germany. It's growing. I'm just trying to do my best to have it evolve over there. I already heard everyone in Berlin was happy for me. They woke up and saw the news. So I'm trying to get more people to transfer from soccer to baseball overseas."
His mom, Kathy, made the trip from Berlin early on Tuesday to see him in the Majors, while his sister, Emma, flew in from Florida. His father, Marek, couldn't make the trip due to work commitments.
Kepler figures to see limited action in the outfield late this season, as he'll be mixed in with Aaron Hicks, Eddie Rosario, Torii Hunter and Byron Buxton.
"Given the circumstances with him coming here with 13 to go, I know a lot about him and talked to Doug and other people in our front office, but it's going to be tough to insert him in there into situations, especially in the short-term," Twins manager Paul Molitor said. "But I know he can run and play defense and he can put together good at-bats vs. righties and lefties. So I'd like to get him exposed a little bit, but don't know how it'll play out."