The notion of eternal recurrence isn't invoked when it comes to sports, probably because we think of our games as being decided by some combination of luck and skill. To start citing, say, "Battlestar Galactica" and its mantra of "everything that's happened will happen again" is to be fatalistic about something that is anything but. Yet, when you think about the intrinsic link between the careers of Clayton Kershaw and Sandy Koufax, it’s easy to think there might be something to this whole eternal recurrence business.

Think about it. For a stretch of five years during the 1960s, Koufax was as dominant as any pitcher has ever been for a span of seasons that long. He was a tough lefty with a wicked, rising fastball and a drop-off-the-table curveball. He wore Dodger blue and, during his prime, played his home games at Dodger Stadium. When his career was snuffed at its height because of debilitating elbow trouble, the blaze of Koufax’s prime seemed like something we wouldn’t see again.

In many ways, watching Kershaw dominate the National League for the past seven years is to get a glimpse of Koufax at his height, only for a longer stretch that shows no sign of abating. That’s a joy for those of us who have seen Koufax pitch only in highlight films. If you’re at all interested in baseball history, it’s hard not to think of Koufax when you ponder Kershaw’s career. Even the great Vin Scully once famously referred to Kershaw as Koufax, and absolutely no one could blame him for the mix-up.

"[Koufax] was a really hard thrower," said Brewers broadcaster Bob Uecker (yeah, that Bob Uecker). "And everybody always talks about how hard Sandy threw, but he had an unbelievable curveball. Probably a major portion of his strikeouts came on that big breaking ball he had. When I look at Kershaw and the way he throws, he's got a more herky-jerky motion and windup. Sandy got on top of that breaking ball and came straight over the top."

You might recognize Uecker from his appearances on Johnny Carson, as "Mr. Belvedere," as Harry Doyle in "Major League" and as the guy on the beer commercial saying, "I must be in the front row." But he also has a unique perspective on the two Dodgers greats, even if they did play a half-century apart. Not only has Uecker called most of the Brewers-Dodgers games since Kershaw came into the league, but, during his playing career -- the subject of his famous self-deprecating humor -- he faced Koufax more often than all but one other pitcher. He was 7-for-38 with three walks against Koufax. He sees a lot of shared traits in the two lefties.

"[Kershaw] is not just a thrower. He can pitch, too," Uecker said. "He can paint the corners and do what he wants. Sandy was kind of the same way. When Sandy was on his game and really right, his fastball was great and his curveball was just so sharp-breaking."

In 1965, arguably Koufax’s best season, Uecker went 6-for-15 against him and hit a home run. For one season at least, Uecker kind of owned Koufax.

"I don’t know why I had success against him," Uecker said. "I played for the most [part] against left-handed pitching. Every time I see Sandy, and I still do it, I always apologize, because I thought I was going to keep him out of the Hall of Fame. He is a great guy and a great pitcher."

What does he remember about that homer off Koufax?

"I remember it was at Dodger Stadium," Uecker said. "I think when I got back to the dugout, the guys were laying on the floor."

The other night in Milwaukee, Kershaw blew past 2,000 career strikeouts, whiffing 14 Brewers and becoming the second-fastest pitcher ever to hit that mark by games pitched (277). Only Randy Johnson (262) got there faster. With Kershaw nearing age 30 (he’ll get there during spring training next year), we’re likely entering into a new phase of Kershaw-related milestones.

"He's in very, very exclusive company," Dodgers manager Dave Roberts said. "The thing that's remarkable about Clayton is that it's a notch in his belt, but I don't think he puts too much credence in that. That says a lot about his character, understanding not only the big picture but his ability to stay micro-focused on today. He's a great pitcher, and for me to be a part of his journey is great."

"[Kershaw] is not just a thrower. He can pitch, too. He can paint the corners and do what he wants. Sandy was kind of the same way. When Sandy was on his game and really right, his fastball was great and his curveball was just so sharp-breaking." Broadcaster and former catcher Bob Uecker on Clayton Kershaw and Sandy Koufax

It’s pretty amazing, really. Not only has Kershaw more or less matched Koufax’s unmatchable peak, but he has done it as a lefty in the same uniform in the same stadium. What are the odds? Don’t ask Kershaw, who isn’t big on talking up his achievements, not even on a night he reaches a concrete milestone like 2,000 strikeouts.

"It'll be cool some day," Kershaw said after the Milwaukee game. "I guess when you retire, you look back on that stuff. I'm not taking it for granted but also not thinking about it, how to quantify it. It'll be cool some day."

He did save the ball, pointing to it in his locker with a jerk of his head, adding, "Hopefully, I don’t forget and leave it behind."

People have been doing analytical comparisons of Kershaw and Koufax for a few years now. It’s prime time to do so, with Kershaw in the midst of a long peak stretch of his career, and Koufax forever frozen in his. Kershaw’s ERA from 2012 through last season (1.92) was 92 percent better than league average. No one else during that span is even close. It was like that for Koufax, too. From 1962 to 1966, Koufax had a 1.95 ERA that was 65 percent above average, best of all pitchers during that span. Juan Marichal was second at 43 percent above average.

That’s only a jumping off point, though, to illustrate just how dominant each pitcher was in his respective era. Baseball in the 21st century might be more different than the era in which Koufax pitched than any other modern epoch except for the dead ball years. Starting pitchers were working from higher mounds. The leagues were smaller by number of teams, and the player pool had yet to be blessed with the large-scale influx of Latin talent we have in the game today. Rotations were smaller, and starters were expected to finish what they started. Lineups weren’t as deep with power hitters.

During both of his last two seasons, Koufax started 41 games, completed 27 and finished with well more than 300 innings pitched. Kershaw led the National League in innings in 2015 with 232⅔, and he has completed 24 games in his career. As illustrated in this excellent and layered comparison published a couple of years back at the Hardball Times, there are an incredible number of adjustments you have to make in order to view the numbers of Kershaw and Koufax with something like an apples-to-apples comparison. Sometimes you have to defer to the eyeballs of someone who has seen both.

"They really are pretty similar," Uecker said. "This guy is a little bigger than Sandy. Both good power pitchers."

The conclusion of the Hardball Times analysis seems about right: Once you adjust for everything you can adjust for, these pitchers were really, really close once they hit their prime. Kershaw realized his potential at an earlier age, hitting Cy Young-level production by 23. Koufax was a bonus baby who never played a day in the minor leagues. Instead, he languished for a few years with control problems that threatened to sink his career. At 22, Koufax walked six guys per nine innings and led the league in wild pitches even though he wasn’t even yet a full-time member of Walter Alston's rotation. Still, he hit his stride by 25, not appreciably different than Kershaw, and more than made up for lost time.

Two things will separate Koufax and Kershaw from here on out. First, Koufax was so overused that his elbow began to turn inward, shortening his arm to the point that he had to have the left sleeves of his suit-coats shortened. In his final year, he won 27 games, led the league with a 1.73 ERA and 317 strikeouts and was named the Cy Young winner for the third time in four years. But he was done, the pain in his arm too great and the advent of Tommy John surgery still years in the future.

"At the end of Sandy’s career, when you looked at his left arm, it started to bend," Uecker said. "He couldn’t straighten it. I wonder what might have happened had he had surgery, what might have transpired down the road."

Meanwhile, if the arguments about Koufax and Kershaw right now are too close to call, this is probably the last year we can have that debate, if it’s not too late already. Because Kershaw shows no sign of slowing down, and with each passing season he sets a new standard for Dodgers pitchers. In fact, among pitchers with at least 1,500 innings, Kershaw’s 160 ERA+ is the best of all time. Others have written this, and it’s true: Because Kershaw has been healthy and benefits from modern-day pitcher usage, in many respects he’s going to show us what might have happened had Koufax not been forced into such an early retirement. Then again, there’s something to be said for going out on top.

"I don't care if [Koufax] told you what was coming," Uecker said. "When Sandy was on his game, he threw so hard and with that curveball, you couldn’t hit him. He does remind me a lot of Clayton personality-wise. Kershaw is a great guy, too."

Besides the question of longevity, the other thing separating Kershaw from Koufax works heavily in Koufax’s favor: postseason performance. Koufax won three rings with the Dodgers, though the first (1959) came before he had reached stardom. In 1963 and 1965, however, Koufax was the winner in four of L.A.’s eight World Series victories. He threw complete games while winning the clinchers in both series, the one in 1965 coming on just two days' rest. His career postseason ERA (0.95) is the lowest of any starting pitcher who logged at least 50 innings in the playoffs. Kershaw’s postseason struggles have been well chronicled. He’s 4-7 with a 4.55 ERA, and his Dodgers have never reached the Fall Classic during his career.

The lack of postseason success has become an unfortunate and largely unfair co-narrative for Kershaw, much like it once was for Barry Bonds, Alex Rodriguez and others who seemingly faltered in the playoffs until they didn’t. One dominant postseason run is likely all Kershaw needs to set things right, especially if it ends with the Dodgers’ first World Series win since 1988. So far this season, the Dodgers own the best run differential in the National League. That matches up with most preseason analytical forecasts, even though the Cubs were a more popular subjective choice.

So Kershaw has plenty of help, and this might be his best chance yet to get a ring. But the Dodgers are far from a sure thing. They are mired in a three-team scrum in the NL West, and as strong as their differential looks, it’s not appreciably better than that of Wednesday’s opponent, the Washington Nationals, who have the NL’s best win-loss record. On top of that, most everyone still expects the Cubs to mount a strong defense of their crown. And whoever survives the NL playoff derby might have to face a Houston Astros team that right now looks historically strong. But whatever happens, Kershaw’s opponents don’t think he really has anything left to prove.

"[Kershaw] has got three really good pitches," said Milwaukee manager Craig Counsell, who as a player went 0-for-2 with a walk against him. "He's a great competitor, never beats himself with walks. He's certainly one of the best that we've seen in major league baseball. He's proven it over a long period of time."

In the end, Kershaw might never be able to close the postseason gap with Koufax. He might have to settle for being the best regular-season pitcher ever and cede the playoff equivalent of that crown to Koufax.

And that might not be such a bad outcome. It might be the exact outcome Koufax would have had were he pitching now. And if Kershaw were shipped back in time, maybe it would be he who polished off the Twins in 1965 but had to retire a year later because of overuse. This is a show the Dodgers have seen before, and it’s not the kind of thing anyone can get tired of.