Adam Wainwright's 2.31 ERA and 106 strikeouts in 116.2 innings are a large part of the Cardinals' MLB-best record. (Dilip Vishwanat/Getty Images)

What do the top three teams in the major leagues by winning percentage all have in common? They're all in the National League Central. As the Wall Street Journal's John W. Miller pointed out on Monday, since the advent of divisional play in 1969, no single division has ever been home to the three best records in baseball, and a division has only produced the two best records seven times in the 44 seasons prior to this one. Here's the graphic that accompanied Miller's piece (via Aaron Hooks):

The Cardinals, having lost Sunday night, are now 47-29, but that's an insignificant change with regard to the above.

The first thing I notice when looking at the graphic is that there are some memorable pennant races on that list. The 1978 American League East battle between the Yankees and Red Sox, which culminated in a one-game playoff, was the best of that bunch, but the 1982 and 1987 AL East and 1993 NL West races also came down to the final day of the season. That's four of the previous seven instances. Of the other three, the 2001 AL West was notable for involving the team with the most regular season wins in major league history, the 116-win Mariners.

That 2001 AL West race is also notable for being the only one of the previous seven to occur during the wild card era, which is significant for two reasons. The first and most obvious is that, for the first time of those seven seasons, the team with the second-best record in the majors was not shut out of the postseason. That was a large argument in favor of the wild card, and in that case it worked perfectly. There was no tight race that was undermined, and no 100-win team that saw its season end without a playoff berth, something that would have been a glaring injustice given that the A's won 10 more games than three division winners that year.

The other reason that 2001 season was significant was that it was the only time during the six-division era that the teams with the top two records in the majors were in the same division, which makes it all the more telling that it took a 116-win team to make that happen. To recalibrate, then, the top two records came from the same division six times in 25 years of four-division play, or once every 4.2 years, but just once more in 29 years of six-division play.

That makes what's going on the NL Central all the more remarkable, though it also suggests that it's all the less likely to last until season's end. After all, the Reds are just a half-game ahead of the fourth-place Red Sox, and we've seen the Pirates suffer dramatic second-half collapses in each of the last two seasons. The chances that the top three records will all still reside in the NL Central come September 30 remain slim. Though given the softening of the other divisions around baseball, seeing the season end with the top two records in the NL Central wouldn't be surprising, even given that 19-year history of six-division play.

The other wrinkle here is the reformatted wild card system. If the Cardinals, Pirates, and Reds do all finish with one of the majors' top three records, all will make the postseason. That has a ring of faireness to it, but given the history above and the fact that all three teams are separated by less than three games in the standings right now, it would also seem to rob us of a potentially classic pennant race.