He was lying in bed at his Little Rock, Ark., apartment around 1 a.m. on Friday morning when Angels general manager Tony Reagins called him.
"I can't even really explain it," the 19-year-old phenom said, seated next to Reagins at a press conference three hours before he started in center field and hit ninth for the Angels against Seattle on Friday.
"You heard me last night, Tony -- I was mumbling the whole time," said Trout, still a bit choked up with an apparent genuine sense of appreciation clouding his voice, causing him to stammer every now and then. "I didn't even think it was real."
Even after Trout's Major League debut was in the books -- he went 0-for-3 with two flyouts and a groundout -- he still struggled to find words to describe the experience. The 40,161 in attendance at Angel Stadium roared with electricity all three times that Trout stepped into the batter's box in the Angels' 4-3 win over the Mariners.
It was enough to give Trout the jitters in his first at-bat, which he called "a dream come true."
"I never felt like that before," he said. "Forty thousand people just cheering you on. It was awesome."
Though Trout wasn't able to contribute offensively, he helped preserve a 3-3 tie for the Angels in the top of the ninth. Franklin Gutierrez bashed a ball to deep right-center that certainly would have resulted in at least a double had Trout not tracked it down at the warning track.
The play gave the 6-1, 200-pounder a chance to flash his top-flight speed as well as his impressive glove work.
"Like I said, Mike Trout's a legitimate center fielder," Angels manager Mike Scioscia said. "As he gets more experience he'll refine some things, but you saw the closing speed. That ball that Gutierrez hit, that was serious closing speed for him to get to that ball as easily as he did.
YOUTH NOT WASTED ON YOUNG
"I can see Peter Bourjos running that down, I see Mike Trout running that down. Maybe Gutierrez can run his own ball down. There aren't many center fielders that have that much closing speed."
Trout's final at-bat of the evening nearly resulted in a hit. He drove the second offering he saw from Seattle reliever Jamey Wright to left-center, making solid contact, but Gutierrez had enough time to track it down for an out. Trout flied out to right and grounded out to shortstop in the second and fifth innings, respectively.
Afterward, Trout appeared to have no problem shaking out the 0-fer debut, saying, "There's always tomorrow, and there's always the next AB [at-bat]."
The Angels announced Trout's callup late on Thursday night, after Bourjos left the game against Seattle with a strained right hamstring. But Bourjos wasn't placed on the disabled list, and instead starting pitcher Tyler Chatwood was sent to Triple-A to make room for Trout.
"Right now, where our team is, he's the best fit to bring us that presence in center field, and we'll see what he can do on the offensive side," Scioscia said. "I don't know if we anticipate this being that long, but it will be an important look for a young player, to kind of see what that monster of the big leagues is about."
Trout, now the youngest player in the Major Leagues, entered the season ranked by MLB.com as the top prospect in baseball. He hit .324 with nine home runs, 11 triples, 27 RBIs and 28 stolen bases in 75 games for Double-A Arkansas this season. He also boasted an on-base-plus-slugging percentage of .950 and walked 38 times.
Trout also became the youngest player to debut in the Major Leagues since the Mariners' Felix Hernandez, last year's American League Cy Young Award winner, who was just shy of being 19 years and four months old when he debuted in 2005. Trout turns 20 next month and is the youngest player to make his big league debut for the Angels since Andy Hassler debuted on May 30, 1971, at the age of 19 years and 224 days old.
Reagins, who said he was impressed by Trout when he saw him in a Double-A game earlier this month, echoed Scioscia's words that Trout is the "best fit" at this time.
"He plays the game the right way," Reagins said. "He plays it hard. He's a professional. We just expect him to come up here and be Mike Trout. Not try to save the franchise or do anything extraordinary. Just come out here and have fun. His athletic ability and overall ability will take care of itself."
Of course, there are risks to calling up a prospect with high expectations. Early struggles can stifle confidence. Scioscia didn't sound too worried in the case of Trout, though.
"I haven't met a young player who's come up here and struggled for a short amount of time that hasn't gone down and been better for it," he said. "When they come back up and understand that experience, they're prepared better for it. I think it will be a great experience for Mike and he wants to contribute. This guy wants to win. He's driven and wants to play well."
The Angels hope that Trout can come close to playing the tremendous defense that Bourjos has provided all season. And offensively, they'll take whatever they can get.
"Certainly on the defensive side he's ready," Scioscia said. "I think it'll be a good experience for him to not only hopefully contribute in trying to win, but just to measure himself against where his career is and against Major League pitching."
Trout took the field on Friday flanked by veterans Vernon Wells and Torii Hunter in left and right field, respectively. Hunter, who made his Major League debut on Aug. 22, 1997, for Minnesota, had some advice for Trout.
"I would tell him to just have fun, enjoy the moment," Hunter said. "You're happy to be in the big leagues. This is your dream. It's a lot of fun. Go out there and have fun and play the game."
Besides being extremely talented, Trout does have another thing going for him -- Friday's game wasn't his first at Angel Stadium. He played in the team's final three Spring Training games here from March 27-29, as well as last year's XM All-Star Futures Game. In that contest he went 2-for-4, doubling and scoring two runs while helping the U.S. team defeat the World Team, 9-1.
As for the pressure and jitters that certainly come with a big league debut, Trout's plan was concise: Keep things simple.
"There's always going to be pressure," Trout said. "Once you get out on the field it's just a game, and I've had fun playing it my whole life."
Jordan Garretson is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.