Baseball by the numbers: The formula behind Kris Bryant beating Billy Williams

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Kris Bryant hits a two-run home run in the eighth inning of Game 4 of the National League Championship Series against the New York Mets. | David Goldman/AP


For the Sun-Times

With the Kansas City Royals newly crowned as World Series champions, it’s Baseball Writers Association of America awards season. First up is Rookie of the Year, and Cubs third baseman Kris Bryant figures to take National League honors.

Bryant hit .275 with Cubs rookie records of 26 home runs and 99 RBI. He finished with a strong .857 OPS, and his 6.5 wins above replacement, as calculated by, were the most among Cubs rookies since the modern AL-NL era began in 1901. The only higher fWAR in Cubs history was 6.7 by pitcher Larry Corcoran, who went 43-14 with a 1.95 ERA in 1880.

The next best NL rookie fWAR this season was 4.9 by the San Francisco Giants’ Matt Duffy, who hit .299 with 12 homers, 77 RBI and a .762 OPS.

When it was pointed out about a month before season’s end that Bryant was headed to the best rookie season in modern Cubs history and that Hall of Famer Billy Williams had a 1.2 fWAR in winning the NL Rookie of the Year Award in 1961, a couple of emails arrived wondering how the disparity could be so large.

Going by the Triple Crown statistics that were the focus of most by-the-numbers discussions for generations, Bryant’s season isn’t that different from Williams’. In close calls, Williams outhit Bryant .278-.276, and Bryant outhomered Williams 26-25. Bryant had a 99-86 RBI edge, but Williams’ total had been the team rookie record until this year.

But modern metrics that reach beyond Triple Crown numbers to measure each player’s overall contribution give edges to Bryant:

– Bryant walked 77 times to 45 for Williams, so even though Williams had a higher BA, Bryant was much better at getting on base. With a .369 on-base percentage to Williams’ .338, and a .488 slugging percentage to Williams’ .484, Bryant had the higher OPS, .857-822.

– Williams played in a more favorable offensive context than Bryant did. NL teams averaged 4.5 runs per game in 1961, but only 4.1 in 2015. Bryant’s 6.8 runs created per game stood much further above the NL average than Williams’ 5.8 runs created per game.

– As a third baseman, Bryant gets a positional adjustment of plus-2.5 runs per 600 plate appearances in the field, while the adjustment for a left fielder, Williams’ position, is minus-7.5 runs. In addition, Bryant played better-than-average defense for his position, at plus-7.1 runs at FanGraphs, while Williams was below average at minus-14.9 runs.

† Bryant gets credit for his skill on the bases with 7.1 baserunning runs, to 1.4 for Williams.

Bryant’s overall offensive game was better, his defense was better, and his baserunning was better.

That doesn’t mean Bryant is a better player than Williams became or that engraving should start on a Hall of Fame plaque. Williams is a Cubs legend; Bryant had a great rookie season. But to those who wondered how two seasons so similar on the surface could be so far apart by advanced numbers, those are the reasons.

Follow me on Twitter @GrochowskiJ.

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