That doesn't mean they won't be chosen for a reserve spot on the team, just that it's a longshot that they'll be voted into the starting lineup by fans. Anyone can be selected through write-in votes, but an unlisted player hasn't been chosen since 1974, when the Dodgers' Steve Garvey was a write-in winner and went on to win the game's Most Valuable Player Award.
In Nieuwenhuis' case, it's possible that veteran Andres Torres will take over in center field when he returns from a calf injury. But Nieuwenhuis is doing all he can to stake claim to the center-field job in Queens, hitting .333 in 48 at-bats with two homers and a .928 OPS.
"He's getting better," Mets manager Terry Collins said last week. "The one thing about Kirk is, he's one of those guys, when he gets hot, you can't get him out. I don't care if you throw right, left, between your legs, it doesn't matter. He can hit you."
As for Sweeney, he's making a good case to stay in the Boston outfield for a long time, as both Carl Crawford and Jacoby Ellsbury are injured. Sweeney has been one of the few bright spots for the struggling Red Sox -- hitting .400 with six RBIs through play on Monday.
"He's played really well for us," Boston manager Bobby Valentine said. "The last four games of Spring Training, he started to feel his swing come around. And he took it right into the season, getting big hits late in the game."
Schierholtz is working similar wonders in the outfield for the Giants, where he was beaten out by Aubrey Huff for a spot on the ballot. His playing time has increased since the start of the season, and he is hitting .372 with three homers. He added six hits on Monday, playing in both games of San Francisco's doubleheader against the Mets.
Speedy outfielders Gerardo Parra (Arizona) and Juan Pierre (Philadelphia) were also not among the National League outfield choices, as neither looked poised to play much at the start of the season. But they have carved a niche with their respective teams because of injuries and solid play.
For the Angels, Mark Trumbo is listed as the club's third baseman on the ballot. It remains unclear how manager Mike Scioscia plans to use Trumbo, a converted first baseman who can also play the outfield, for the remainder of the season.
If Scioscia opts to move Trumbo -- a defensive liability so far -- away from the hot corner, that opens up room for Alberto Callaspo and Maicer Izturis to play more often. Thus far, Callaspo has struggled, but Izturis is hitting .320 with a .433 on-base percentage and three steals in his nine games, all while playing sparkling defense.
Obviously, there is plenty of time before the winners are chosen, and a lot can happen to those supposed snubs who have gotten off to hot starts. But for the players who weren't included on the ballot, we will see what the future brings.