Earlier this season, Angels manager Mike Scioscia said that Trout could end up being a "special player."
Trout was to wear No. 27 Friday against the Mariners, a number last used by Vladimir Guerrero, the former Angels slugger and 2004 American League MVP.
Trout's mother, Debbie, caught a plane Friday afternoon to see her son play.
"We are so excited I can't even describe it," she said.
According to baseballreference.com, Trout will be the youngest player to debut since pitcher Felix Hernandez, then 19, debuted with the Mariners on Aug. 4, 2005.
Trout, the 25th overall pick in the 2009 draft, bats right and throws right. He hit .276 in 16 spring-training games for the Angels and is ranked by several scouting services as the top prospect in all of Major League Baseball. He was the Topps' 2010 Minor League player of the year - the youngest ever - and the Midwest League MVP with single-A Cedar Rapids.
"Mike is close to being a five-tool player, if not a five-tool player with a great makeup," Abe Flores, the Angels' director of player development, said in August. "He's driven and coachable, and he's a winner."
Shortly after signing a contract with a $1.215 million signing bonus, Trout made the transition from high school to professional baseball appear seamless when he tore through the Arizona League. In 39 games in 2009, he batted .360 with 25 RBIs and 13 stolen bases. He began the 2010 season with Cedar Rapids and hit .362 with 39 RBIs and 45 stolen bases in 81 games before he was promoted to the single-A California League last July.
At last year's Futures Game during all-star weekend, Trout reached base in each of his four at-bats - twice on hits, twice on errors - and he was timed running down the first-base line in 3.9 seconds. He stood out among the rest of the young players because of his hell-bent style and baseball IQ as well as his talent.
"It was great to play in Anaheim in front of all the Angels fans, and play at the stadium," Trout said last July. "It was just a thrill."
Trout's father, Jeff, who starred at the University of Delaware, played four years in the minors in the Twins organization. One of his managers was Charlie Manuel.
Flores said Trout has the skill set of a centerfielder but can play all three outfield positions.
"He's determined, aggressive," Flores said in August. "We're very excited about him."
Contact staff writer Gary Miles
Staff writers Marc Narducci and Ray Parrillo contributed to this article.