NL Rookie of the Year No Longer a Two-Horse Race

Heading into the season, Kris Bryant enjoyed favored status when it came to predicting a National League Rookie of the Year. When FanGraphs writers were polled before the season, 20 of 36 votes went to the Chicago Cubs’ third baseman; seven went Joc Pederson; six were cast for Jorge Soler; Noah Syndergaard, Jung Ho Kang and Raisel Iglesias each got one. A couple months into the season, Pederson inserted himself into the race with 13 home runs by the end of May. As the year has moved on, Bryant and Pederson have come back to the pack a bit while Matt Duffy, Kang and Syndergaard have moved into the conversation for the NL’s top rookie. The award is no longer a two-horse battle, and all the players who have risen up are sure to see plenty of exposure since each of them is in the middle of a pennant race.

As Owen Watson wrote, this season has been a historic one for rookies, particularly position players. With Bryant and Pederson leading the way, the rookie class is producing at a greater level than any in the past decade. It’s likely the best class in nearly 30 years, back when Barry Bonds and Jose Canseco were rookies. In the past month, Bryant and Pederson have allowed a few other players to enter the race. Pederson — a three-true-outcomes player to begin the season — has removed the two positive outcomes over the past month, walking just 3% of the time and hitting only one home run. Bryant hasn’t fallen quite as far. He’s still drawing walks, but he is striking out nearly one-third of the time and has a wRC+ of 58 over the past 30 days.

Even with the drop, Bryant is still in an excellent position to take home top rookie honors in National League. While Pederson and Bryant were the only rookies with WARs above three at the All-Star break, Pederson has dropped below that level. Meanwhile, the Giant’s Duffy has joined Bryant with 3.1 WAR on the season. Duffy isn’t the only player trying to put himself into the conversation, though. Maikel Franco looked like he might make for a strong third-place finisher early in the season, but he has had only one great month. Kang has excelled after receiving consistent playing time following injuries to Josh Harrison and Jordy Mercer. Randal Grichuk is riding an extremely high BABIP and a ridiculously high ISO to put up some of the best offensive numbers in this year’s rookie class.

The graph below shows cumulative offensive runs above average by month for the NL rookie hitters with the month line showing where each player stood at the end of the described month.

The graph illustrates the large gap Pederson and Bryant once had over the rest of the class. At the beginning of July, no other rookie was within five runs of the pair. The graph also demonstrates the dropoff for both Bryant and Pederson, as both players have hit below league average since the beginning of July. If Franco could have replicated his June in July, he might still be in the running. During that time, Kung and Grichuk have surpassed Bryant offensively, although neither player has reached the heights of Bryant’s first three months. Duffy has also moved past Pederson offensively with consistent production for the Giants.

Of course, ROY isn’t limited solely to position players, and two pitchers have a shot at staking their claim to the award. Chris Heston has provided solid production for the Giants. He also has a no-hitter to his name, plus 11 wins for those voters who pay attention to that particular statistic. Heston doesn’t have the production of Syndergaard, who put his arsenal on display on Sunday night against the Washington Nationals. With nearly 100 innings on the season, Syndergaard’s sub-three FIP and ERA are both in the NL’s top 10. Adding in Syndergaard and Heston to the players above — and using WAR instead of offensive value — give us this:

Bryant still leads the NL’s excellent rookie class, but Duffy isn’t far off. In addition to Duffy, Grichuk, Kang, Pederson and Syndergaard are all within striking distance. Kang — a 28-year-old who signed with the Pittsburgh for four years and $11 million after a $5 million posting fee to his former team in Korea — has proved to be a bargain for the Pirates. He’s been incredibly important when the team suffered injuries to its regular starters, and it seems likely Kang will continue to receive significant playing time down the stretch even when those injured players return.

One shared feature for Kang, Duffy and Grichuk are high BABIPs. Kang is at .354, Duffy is at .346 and Grichuk is at an absurdly high .382 on the season. Grichuk has struck out in more than 30% of his plate appearances and he’s walked in just 6%. Yet with 37 extra base hits, compared to 33 singles, he’s managed to provide excellent offensive production in 263 plate appearances. His plate appearances and some of his counting stats are behind Bryant and Pederson, but even if Grichuk closed the gap in playing time, sustaining those stats seems questionable. Duffy and Kang might be more likely to continue with high BABIPs, but the projection systems assume a bit of regression is headed both of their ways.

The chart below shows each rookie’s current WAR and the rest of the season projection from the FanGraphs Depth Charts. The third column adds the first two, showing the expected WAR at the end of the season.

Despite Bryant’s recent struggles, the projections have the most faith in him. Bryant was the favorite at the beginning of the year, he’s the leader right now, and the projections still have him ahead at the season’s end. Bryant is closing in on a five-win year, a feat achieved by only fifteen rookies in the past 30 seasons. The most recent player to reach that number also happens to be the leader of that list: Mike Trout.

With seven National League rookies seasons of at least 3 WAR, this rookie class is one of the best Major League Baseball has seen in a while. The race for the league’s best rookie, once almost preordained — then a battle between Bryant and Pederson — has now opened up. The last few months should provide for an interesting battle. With all the candidates on teams fighting for playoff positions, rookies could have a big impact on the pennant race this year.