HOUSTON -- Mike Scioscia will never forget the first time he laid eyes on Mike Trout. He was 17 years old then, not far removed from becoming the Angels' first-round Draft pick and not yet fully grown into his body. He picked up a wooden bat on that summer day in 2009, stepped into the batter's box at Angel Stadium for a showcase round of batting practice and began to drive balls the other way, a handful of rows behind the tall scoreboard in right-center field.
"The scouts were telling us, 'You just have to see this kid when he grows up,'" Scioscia recalled. "What was it, two years later, when he grew up?"
Trout is fully grown now. On Tuesday night, in the early stages of an eventual 4-3 win over the Astros, he reached 40 home runs for the first time in his career, joining Troy Glaus -- 47 in 2000, 41 in '01 -- as the only players in Angels franchise history to hit that many.
"It's obviously special," Trout said of reaching 40. "Coming into the season, I thought it would be pretty special, pretty cool, and it happened."
Trout jumped on a first-pitch 94-mph fastball from Astros right-hander Lance McCullers in the first inning and launched it off one of the advertisements way up in left-center field for a two-run blast, marking only the second time he has homered on the first pitch this season. Immediately after that, Albert Pujols lined his 556th career home run to pass Manny Ramirez for sole possession of 14th place on the all-time list.
Trout has 138 career home runs, more than any other center fielder through his age-23 season -- and few could've ever imagined the power coming so quickly.
Trout was never anything less than one of the most captivating prospects in the game, but he managed only 23 home runs in the 286 games that made up three-plus seasons in the Minor Leagues. Then he grew older, stronger, and quickly morphed into one of the elite power hitters in the Major Leagues.
Trout went from homering once every 49 at-bats in the Minors to once every 17 at-bats in the Majors. He hit 30 as a rookie in 2012 -- despite spending the season's first month in Triple-A -- then 27 in '13 and 36 in '14. He's on pace for 43 this year.
"Every year, I get more comfortable out there," said Trout, sporting a .293/.395/.584 slash line this season. "That's the biggest thing. Experience and playing every day and seeing the pitchers more than once, it helps you out."
Trout, who didn't turn 24 until Aug. 7, is one of six American League outfielders to hit 40 home runs before their age-24 season, joining Juan Gonzalez, Ken Griffey Jr., Jose Canseco, Reggie Jackson and Joe DiMaggio.
But his manager still doesn't see him as a home run hitter, per se.
"Obviously, he did it, he has the potential to do it, but I don't know if that's his baseline year where you're going to see him hit 40 to 50 home runs," Scioscia said. "He's just too good a hitter. He's going to hit .300 every year; he's going to work counts."
Said Trout: "I just try to put good swings on the ball, and they go out."
Alden Gonzalez is a reporter for MLB.com. Follow him on Twitter @Alden_Gonzalez and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.