If he retires now, he's absolutely a Hall of Famer.
We're giving far too much credit to guys who had long careers. Longevity should be a factor, but not
nearly as big a factor as dominance. Clayton Kershaw has been, hands down, the best pitcher in the game the last six seasons. And he was pretty darned good the two before that amazing six year run. And, like Koufax, he had inarguably his best season at the end. If this is it for Kershaw (it won't be), he's one of the greatest to ever play his position. That he dominated at a ridiculous level as a left handed pitcher only adds to his stature.
He was a rookie at 20, and had a 4.29 ERA. In the eight seasons since, he's never had an ERA above 3.00. He's led the league in ERA five of the last six seasons, and the one he didn't lead, his ERA was 2.13. How good has he
really been? Through the history of baseball (with complete statistics going back to 1901, so 115 years of the sport),
only two pitchers have been more dominant through their first nine seasons (1,000 innings pitched, minimum): Walter Johnson and Pedro Martinez.
Career ERA + through nine seasons:
Walter Johnson 176
Pedro Martinez 168
Clayton Kershaw 158
Then, let's look at FIP. Again, FIP (
fielding independent pitching) measures only the things a pitcher can control: home runs surrendered, hit batsmen, walks, and strikeouts. Through nine seasons,
Clayton Kershaw ranks 32nd of all starting pitchers in FIP (again, 1,000 innings pitched, minimum).
But here's the caveat.
All thirty-one pitchers on the list ahead of Kershaw played in the dead ball era, when home runs were rare. They should have a lower FIP metric than Kershaw because the game was different. This means that, when considering only things a pitcher can control, eliminating things like wins, runs allowed, hits allowed, etc, all of which the team behind the starter can heavily influence, Clayton Kershaw is the best starting pitcher of the modern era. Not top ten. Not top five. Number one.
2,000 innings pitched, or 3,000 innings pitched is some arbitrary number picked out at random because people like nice ever numbers. 3,000 hits. 3,000 strike outs. 500 home runs. As if Frank Robinson would be judged differently if he'd somehow managed 57 more hits to reach 3,000, or Fred McGriff would suddenly be a Hall of Famer if he'd hit 7 more home runs. Clayton Kershaw has thrown 1,732 innings in the Major Leagues, more than enough time to demonstrate how he throws the ball, and more than enough time for Major League hitters to adjust, if they could, and improve their fortunes against him. Nine years into his career, not only have they not figured him out, but Kershaw is getting better. In the past six seasons, he's won an MVP, three Cy Young Awards, and he's finished second and third in the voting once each. If the season ended today, he'd be a unanimous Cy Young winner for 2016.
Look at his past three seasons, and how spectacular his numbers are. 48-12 (an .800 winning percentage), 1.92 ERA, 552 IP, 13 CG, 8 SHO, 685 K, 82 BB, 190 ERA +, 1.85 FIP, 0.839 WHIP, 11.2 K/9 IP, 1.3 BB/9 IP, 8.35 K:BB.
Look at his Hall of Fame metrics:
Black ink: 65 (16th all-time), average HoF 40
Gray ink: 154 (92nd all-time), average HoF 185
Hall of Fame Monitor: 123 (64th all-time), average HoF 100
Hall of Fame Standards: 46 (48th all-time), average HoF 50
He's already met the Black Ink and Hall of Fame Monitor metrics in nine seasons. He's 4 points off the Hall of Fame Standards, and 31 points off of Gray Ink. All in, being accurate, 8.5 seasons as a starter.
I don't see an argument that could be made keeping Kershaw out of the Hall of Fame. He's simply one of the most dominant starters the game has ever seen. If the Hall of Fame rewards true excellence, how can he be kept out?