Mike Trout
On April 17, 2015, Trout became the youngest player in MLB history to reach 100 home runs and 100 stolen bases. He was 23 years and 253 days old when he reached the milestone, passing the previous record-holder, Alex Rodriguez, who had achieved it at the age of 23 years and 309 days in 1999. Trout led off the 2015 MLB All-Star Game with a home run, becoming the fourth player in All-Star Game history to do so. For the second year in a row, Trout won the All-Star Game MVP Award, becoming the first player ever to win it in consecutive years. On September 22, Trout hit his 40th home run, becoming only the second Angels player to hit 40 home runs in a season. Trout led the AL in WAR for the fourth straight year.
Madison Bumgarner
On September 8, at AT&T Park, Bumgarner was called up to the Majors for his first start, making his Major League debut against the San Diego Padres in place of ace Tim Lincecum, who was scratched with back spasms. At the age of twenty, he became the second-youngest pitcher ever to start a game for the Giants, and the youngest since the franchise moved west in 1958. He was older only than Mike McCormick, who started two games for the Giants—as a nineteen-year-old—in , when the team was still in New York. In the bottom of the third inning with no outs, Bumgarner struck out opposing pitcher Kevin Correia for his first career strikeout. Three days later, fellow star prospect Buster Posey made his Major League debut. Bumgarner made four appearances with the Giants in 2009, posting an ERA of 1.80, striking out ten batters, and pitching ten innings.