Trout was selected 25th overall in the 2009 draft, while Harper was the first pick the next year. They've both enjoyed meteoric success since with each named to their respective leagues' All-Star teams each of the past two seasons. Trout leads baseball in runs scored since the 2012 season with 252 while his .979 OPS in that span trails only Miguel Cabrera.
While injuries limited Harper to 39 fewer games over the past two seasons, his .834 OPS still ranked seventh among National League outfielders. His 22 homers, 98 runs and .477 slugging percentage in 2012 were all franchise rookie records, while his nine triples tied Andre Dawson for the most by a rookie in club history.
The two stay in touch, though they're not extremely close, Trout told the team's website.
"We're both position players, so we're not really going to face each other," said Trout, who is hitting .307 with 12 extra-base hits. "We're both going to try, obviously, to get on base, get some hits. But I think when you try to do too much, that's when you get in trouble."
Neither player enters the series on a particularly high note, though at least Harper's club comes off a victory with Sunday's 3-2 walkoff triumph over St. Louis. The Angels (8-10), who are playing their fourth game on a nine-game trip, were held in check for the second straight game in a 2-1 loss at Detroit, managing seven hits after being held to four in a 5-2 defeat a day earlier.
Trout - who struck out four times for the first time in his career Saturday - was 0 for 3 with a walk Sunday and grounded out with the tying run in scoring position in the eighth. He was also one of three Angels to commit an error on one play in the bottom of the first. Los Angeles had committed only nine errors through its first 17 games before being charged with four Sunday.
The Nationals (11-8) continue a season-high 11-game homestand after Denard Span's sacrifice fly brought home the winning run in the bottom of the ninth against the Cardinals on Sunday.
Harper was 1 for 4 after being yanked by manager Matt Williams in Saturday's 4-3 loss. Williams cited a "lack of hustle" when Harper jogged halfway down the first-base line after hitting a comebacker to the mound in the sixth inning, and Harper said he respected Williams' decision.
After hitting .483 during an eight-game hitting streak, Harper is 2 for 15 in four contests since.
He'll try to pick it up against Angels starter Garrett Richards (2-0, 2.84 ERA), who is 1-0 with a 1.83 ERA in three career interleague starts. Richards gave up five runs in seven inning in a 10-9, 11-inning loss to Oakland on Tuesday. He limited Houston and Seattle to a combined one run over 12 innings in his first two road outings.
The Nationals will call on Tanner Roark (1-0, 5.29), who didn't record a decision after throwing a season-high 6 1-3 innings in Wednesday's 6-3 win at Miami. Roark allowed three runs, all on a Derek Dietrich homer.
Los Angeles owns an 8-4 all-time edge against the Nationals franchise and swept all three games at home in their most recent series in 2011.