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Kershaw vs. Koufax and the New Standard of Pitching Excellence

By: Stats Perform

This November, when Clayton Kershaw wins his third NL Cy Young in four seasons and possible first MVP Award, the historical comparisons are sure to follow, and certain defenders of golden-age baseball will snap back as dismissively as a Joe Morgan Hall of Fame ballot.

The only pitchers to better Kershaw’s Cy Young streak in four-year terms, Greg Maddux and Randy Johnson with four straight, will be among the names mentioned. Pedro Martinez’s dominance at the turn of the hitter-happy millennium will come up.

And so will the legendary run of fellow Dodgers ace Sandy Koufax, who won three of four such awards when the annual prize was limited to one pitcher across both leagues. In fact, it’s his work that might most closely and conveniently resemble that of the current Los Angeles lefty.

But the prevailing thought that Kershaw is inching closer to Koufax is a bit unfair.

He’s already there.

Discussions comparing eras often fall into frivolity and unsound logic, a dad telling his son only he saw true greatness, with conclusions settling on the realization that it’s ultimately impossible to send Player X into Player Y’s environment as if you were sizing up a shark fighting a lion in the desert.

But with baseball, the argument of eras rarely seems to include the most relevant comparatives of statistics. An ERA was different in the 1960s, so a pitcher’s numbers from that era shouldn’t be compared directly to that of one from the 2010s. A greater insight of effectiveness comes from adding a layer of context by comparing the differentials pitchers post against their own eras.

Koufax became synonymous with dominance over his last five seasons, leading the NL in ERA in each (1962-66) in what is often referred to as the greatest sustained stretch of pitching in major league history. He was a six-time All-Star from 1961-66, which also happened to be his last six seasons in the majors. Kershaw has led MLB in ERA in four straight seasons with six straight years with a sub-3.00 mark.

A logical jumping off point then seems to be considering the collective work of the last six seasons of each career.

Spoiler: If Kershaw retired today, he might be the better pitcher.

From 1961-66, Koufax posted a 2.19 ERA, 0.97 WHIP, .197 opponents’ batting average and .542 OPS-against. Kershaw’s last six seasons (2009-14), which also happen to be his only full years in the majors, have featured a 2.33 ERA, 1.02 WHIP, .204 OBA and .565 OPS. Leaving the argument at that, Koufax has the slight edge.

But from 1961-66, the NL had a 3.64 ERA, 1.29 WHIP, .254 batting average and .697 OPS. That gives Koufax differentials of 1.45 in ERA, 0.32 in WHIP, .057 in OBA and .155 in OPS.

From 2009-14, NL pitchers had a collective 3.90 ERA, 1.32 WHIP, .254 OBA and .718 OPS. That gives Kershaw differentials of 1.57, 0.30, .050 and .153. So the differential in Kershaw’s ERA against the league ERA is actually more drastic than Koufax’s while the elder’s WHIP, OBA and OPS are slightly more impressive. But those numbers don’t take into account that Kershaw faced AL teams in 17 starts. As would be expected, each of those seasons featured more offense in the Junior Circuit. Koufax never pitched a game against a designated hitter.

Kershaw’s last two seasons have featured two of the 15 lowest single-season OPS-against marks since 1914 with back-to-back years of .521. Three of the lower numbers belong to Koufax (.501, 1963; .507, 1965; .516, 1964).

Again, at first glance, Koufax’s numbers look more impressive, but we need to consider the eras in which each pitched. The NL OPS in 2014 was .694. In 2013, it was .704, which ranks just below the all-time average of .706. It was .669 in 1963, and .685 the next two seasons.

That makes Kershaw’s 2013 gap of .183 between the league average and his league-best mark greater than any of Koufax’s three prolific seasons. Those numbers as well don’t take into account that Kershaw has faced an average of 2.8 AL lineups per season.

Both Koufax and Kershaw experienced increased dominance at the end of their six-year spans, and Koufax saved his best ERA for last, posting a 1.73 in his 27-9 1966 season. It’s an ERA Kershaw just missed this year with his career-best 1.77. Those stand as two of the 15 best single-season ERAs dating to 1920, with Koufax adding his 1964 mark to the list.

But again, the difference is the 2014 NL ERA was 3.66 while the 1966 mark was 3.61. Kershaw’s differential is slightly better even without factoring in adjustments for his three starts against the AL.

The variable none of this takes into account is fielding-independent pitching, which quantifies a pitcher’s ability to prevent home runs, walks and hit batters while causing strikeouts. Koufax’s FIP for his six years was 2.26. Kershaw’s is 2.61, and his 1.29 differential from the NL mark doesn’t quite match Koufax’s 1.38 number, but again, we need to consider pitching against the AL.

Kershaw’s evolution as a pitcher, however, might best be made evident by his 1.78 mark in 2014, which Koufax never matched. Kershaw’s differential from the 2014 NL mark of 3.66 was a staggering 1.88. Koufax’s best FIP of 1.87 in 1963 featured a differential of 1.42.

If the minor differences between these numbers aren’t enough, the kicker might come in considering the across-the-board dominance Kershaw just completed at age 26.

Kershaw led MLB in wins (21), winning percentage (.875), ERA (1.77), FIP (1.78), WHIP (0.86), OPS (.521) and strikeouts per nine innings (10.8), a list Koufax matched in 1965 but hasn’t happened since Martinez in 1999. The only blemishes to Kershaw’s dominance in 2014 were that Johnny Cueto’s .194 OBA beat out Kershaw’s .196 mark, while Phil Hughes (11.63) far surpassed Kershaw (7.71) in strikeout-to-walk ratio.

Koufax posted gaudy strikeout totals, but he never matched Kershaw’s 2014 K/9 mark. What’s significantly more impressive about Kershaw’s 10.8 rate is that he also posted baseball’s lowest pitches per inning (13.7), which seems nearly impossible to accomplish with so many strikeouts. Checking pitch-count data available from 1988 on, Kershaw is the first to lead in both.

The list goes on. Only four pitchers dating to 1914 have had a higher winning percentage than Kershaw in 2014 while also winning at least 20 games (Ron Guidry, 25-3 in 1978; Lefty Grove, 31-4 in 1931; Cliff Lee, 22-3 in 2008; Preacher Roe, 22-3 in 1951), though Greg Maddux’s 19-2 strike-shortened 1995 season probably deserves mention considering he made more starts and pitched more innings than Kershaw.

This is all without getting into ERA+, which considers a pitcher’s ballpark and league ERA, and also favors Kershaw (160) over Koufax (156) during their six-year periods.

Still, the difference between Koufax and Kershaw is often negligible. Both have posted back-to-back sub-2.00 ERAs (Kershaw in 2013-14, Koufax in 1963-64). They’re two of four pitchers since 1955 to post sub-2.00 ERAs and FIPs in the same season (Kershaw in 2014, Koufax in 1963). Very shortly, both will have three Cy Youngs to their credit.

So perhaps the bigger philosophical point should be that while Koufax’s numbers came at another time, benchmark reputations need to be constantly reanalyzed. For all of Koufax’s greatness, the fish seems to have grown even though it was long ago mounted, a nostalgic attitude that follows that era of baseball possibly more than any other era in any other sport. There’s a line in Woody Allen’s “Midnight In Paris”:

“Nostalgia is denial – denial of the painful present. The name for this denial is golden-age thinking – the erroneous notion that a different time period is better than the one one’s living in. It’s a flaw in the romantic imagination of those people who find it difficult to cope with the present.”

That romanticized ideal seems inexorably tied to Koufax more than maybe any other pitcher, due in large part to the way he left the game: At his best, yet saddled with an ailing left arm, leaving then-young fans longing for more, unwilling to accept him being rivaled. But those numbers are being matched and possibly bettered right now by someone from his own franchise, and they’ve been bettered at other times since (See: Maddux and Martinez).

Joe Morgan was a .241 hitter against Sandy Koufax. He struck out seven times in 29 at-bats. Not terrible for numbers against Koufax. But there’s no reason to believe he’d be any better against today’s Dodgers ace. A shark out of water then would still be a shark out of water now.