He was rewarded by making his Major League debut in the ninth inning as a defensive replacement in Tampa Bay's 5-2 win to advance to Wednesday night's American League Wild Card Game against the Indians at 8 p.m. ET on TBS.
It was a rare occurrence, as he became the first player to make his Major League debut in a single-game tiebreaker. He also became just the second player to make a debut in his club's 163rd game or later, joining the Yankees' Elvio Jimenez, who played in his first big league game in New York's 164th game of the 1964 season, according to the Elias Sports Bureau.
"There's not a whole lot of guys who made their debut in a Game 163 so to be able to do that, it was just a crazy day," Kiermaier said. "I really can't thank these guys enough for bringing me up here to be a part of this. It's so much fun. We'll see what happens the rest of the way."
Kiermaier isn't likely to be added to Tampa Bay's postseason roster, but he impressed the organization with his play in the Minor Leagues, especially defensively. The 23-year-old also hit a combined .295/.362/.431 with 42 extra-base hits and 21 stolen bases in 136 games between Double-A Montgomery and Triple-A Durham.
He said he was told before Monday's game he'd likely see action with center fielder Desmond Jennings dealing with a tight left hamstring so it helped him calm his nerves when he finally saw action.
"I knew it was my role so I expected to come in at some point," Kiermaier said. "But to come in up three in the ninth was good because I wasn't that nervous. The pressure was all on them. With the way Price was throwing, I wasn't surprised nothing was hit my way. But it was a great MLB debut with those circumstances coming in for the ninth in Game 163."
Rhett Bollinger is a reporter for MLB.com. Read his blog, Bollinger Beat, and follow him on Twitter @RhettBollinger. This story was not subject to the approval of Major League Baseball or its clubs.