The American League leaders in the outfield are Josh Hamilton, Curtis Granderson and Nelson Cruz. Mark Trumbo, another young Angels standout worthy of All-Star consideration, is sharing the outfield with Trout these days but is listed on the ballot at third base, a position he rarely plays.
The leading vote-getters among NL outfielders are Matt Kemp, Carlos Beltran and Ryan Braun. It would take a virtually unprecedented late surge for Trout or Harper to land a starting role.
Not since 1974, when first baseman Steve Garvey powered his way into national prominence with the Dodgers, has a player made an All-Star Game starting lineup as a write-in choice. Garvey expressed his gratitude to fans with a Most Valuable Player performance in Pittsburgh for the winning National League side.
The rapid emergence of Harper and Trout -- Scottsdale Scorpions teammates in the 2011 Arizona Fall League -- is stunning given that they are the two youngest players in the Major Leagues.
Harper, 19, hopes to celebrate his 20th birthday on Oct. 16 in the midst of a postseason run. Trout turns 21 on Aug. 7. Both are advanced far beyond their years, blessed with the skill sets and instincts of players in their late 20s.
Through his first 41 Major League games, Harper is hitting .303 and slugging .548 with a .384 on-base percentage for a .933 OPS. Along with seven homers and 19 RBIs, he has eight doubles and four triples, scoring 30 runs.
Trout, already one of the game's most electric leadoff men, is batting .341 through 41 games, with .401 on-base and .541 slugging percentages creating a .942 OPS. Trout has gone deep six times and driven in 26 runs while scoring 35, and he's the league leader with 16 steals in 19 attempts.
Even if their write-in campaigns don't generate enough votes for them to crack the starting lineups, Harper and Trout are candidates to make the trip to Kansas City as All-Star reserves.
Few players in the game, at any age, can match the all-around skills, energy and fan appeal of the two prodigies.
"Bryce is so driven," Nationals manager Davey Johnson said. "A lot of times he tries to do too much. He's much more driven than anyone I've seen. He wants to be a very good player.
"He's just a gifted athlete. I like everything about the way he plays the game. He plays hard. Old school."
Harper, arguably the most hyped position player since Ken Griffey Jr. broke into Seattle's lineup in 1989 at 19, was remarkably poised and comfortable from day one with the Nationals.
In his sensational April 28 MLB debut against the Dodgers in Los Angeles, Harper showcased his quick, powerful bat, plate discipline, plus speed and powerful arm in left field.
Afterward, dismissing the notion of anxiety, he said: "I really didn't have any butterflies. I had that fire and passion back in my game after [enduring] the 25-degree weather [at Triple-A Syracuse]. Coming here, playing with a winning team like we are, it's a great opportunity to play and have that passion back."
Quickly moving up in Johnson's lineup from seventh to second, Harper confidently put it all together.
Combining superlative offensive and defensive skills, Trout has been a driving force in the Angels' rise after a dismal start.
"I don't want to have any distractions for him," Angels manager Mike Scioscia said when asked about Trout's write-in chances. "Even if he doesn't get there this year, it's only a matter of time that he's going to be an All-Star.
"He was further advanced than any 19-year-old I've seen last year, and he's shown that at 20. He has an all-around game, and even though experience will be a great teacher, he's way ahead of the curve at 20 years old."
Trout said he was "flattered" by the way fans have responded to his play, adding that "it's an honor if they feel like voting for me. Naturally, it would be a thrill to be in the All-Star Game."
Harper has been on an accelerated schedule since his early teens in Las Vegas, seemingly predestined to be the No. 1 overall pick in MLB's First-Year Player Draft. It became official in 2010, the Nationals awarding him a five-year, $9.9 million contract running through 2015.
Trout, a multisport star in Millville, N.J., made baseball his primary focus in his sophomore year of high school and was the Angels' second first-round pick, No. 25 overall, in 2009. He rocketed through the farm system, making his Major League debut on July 8, 2011 and playing 40 games as a backup in two stints.
Like Harper, Trout made it to the Major Leagues at 19 -- struggling first time around last season, looking like a seasoned pro when he was recalled from Double-A Arkansas.
In part because he missed much of Spring Training with a respiratory infection and also because the Angels had an outfield packed with proven talent, Trout opened the season at Triple-A Salt Lake.
Abusing Pacific Coast League pitchers with a .403/.467/.623 slash line for 20 games, Trout was summoned to Anaheim on April 28 and immediately showed he belonged.
Rarely in the game's history have two talents this extraordinary arrived simultaneously. Old-timers with long memories might compare it to the arrivals of Willie Mays and Mickey Mantle in New York in the early 1950s.
While Harper has the power to challenge for NL home run and RBI crowns, Trout is likely to be contending for multiple AL batting and stolen base titles.
Seizing center field from 2011 sensation Peter Bourjos, one of the few players in the game with Trout's speed and defensive skills, Trout has made the sensational play almost routine. He shifts comfortably to left when Bourjos plays.
Playing all three outfield positions in Washington, Harper also has shown superb skills with less speed but a stronger arm than Trout.
Packages don't come much more complete -- or entertaining -- than these two.