It's certainly possible that I'm missing someone. I've been known to occasionally miss someones. But it sure looks to me like there are only four, maybe five National League Rookie of the Year candidates worth more than a few words of dismissal.
Running quickly through the impressive starting pitchers, you've got Vance Worley (8-1, 2.76), Cory Luebke (5-6, 2.99), Brandon Beachy (5-2, 3.43), Josh Collmenter (7-7, 3.47) and Dillon Gee (11-4, 3.92). A starter needs to win at least 12 games to get a sniff from Rookie of the Year voters, and only Gee and Worley are going to get there. Gee's likely to finish with a pretty impressive record, Gee with a pretty impressive ERA. But without both, a starting pitcher's probably out of luck.
Atlanta's Craig Kimbrel is almost certainly going to crush the rookie record for saves this season. And it's not like he just happens to have that job; Kimbrel's numbers, just in case you haven't noticed, are utterly brilliant across the board. Award voters don't generally care much for relievers (and they shouldn't) ... but Kimbrel's gotta be a top Rookie of the Year candidate.
Among the NL's rookie hitters, only Freddie Freeman and Danny Espinosa look like legitimate Rookie of the Year candidates. Freeman got off to a slow start, but has been fantastic since April. Espinosa got off to a pretty good start, but has struggled terribly since the All-Star break and is looking at some bench time. Wins Above Replacement still likes Espinosa -- and for that matter, Darwin Barney -- over Freeman, because of defense and baserunning. But the voters are going to look at hitting stats, and right now that's Freeman in a walk.
According to the landscape today, I suspect Kimbrel and Freeman will fight for the award, with Espinosa and Worley scrapping for third. But a lot might happen in six weeks.