On Tuesday, Jon Heyman reported that Davey Johnson really wants Bryce Harper to begin the season as his everyday right fielder. While we don’t have a direct quote from Johnson confirming the story, given the fact that the alternative is some combination of Roger Bernadina, Mike Cameron, and Xavier Paul, it’s understandable that Johnson would prefer the uber-talented Harper in his quest to win games.
Managers always want to put the best players on the field that they can. Their job is to maximize performance in the short term, and given the choice between a raw potential superstar or a mediocre role player with limited upside, they’re going to take the kid nearly every time. However, this is also why managers aren’t allowed to make these calls, and Bryce Harper’s opening day assignment will be decided by the team’s front office.
For the Nationals, this should be a pretty easy call. The 19-year-old Harper looks to be a special talent, but even the very best 19-year-olds are generally not great Major League players. In the history of the sport, 16 guys have gotten 100 or more plate appearances in the Majors at age 19 or younger and been above average Major League hitters – the list includes Ty Cobb (134 wRC+), Mickey Mantle (114 wRC+), and Ken Griffey Jr (106 wRC+). If we assume that Harper is that kind of talent, maybe we could pencil him in for a 110 wRC+ or so this season. If he’s more like previous elite teenage prospects B.J. Upton (93 wRC+), Robin Yount (90 wRC+), or Mike Trout (88 wRC+), he’ll likely face his share of struggles and contribute minimal value to the team.
The Nationals simply should not trade team control of Harper’s age-25 season in exchange for getting a few hundred additional at-bats from him this year. The marginal value of having him on the roster from day one is massively outweighed by keeping him from hitting free agency after the 2017 season. Johnson may want Harper, but he shouldn’t get him until June at the earliest.