Since May 31, these are their records:
Pittsburgh: 48-24 (.667)
St. Louis: 45-28 (.616)
Chicago: 45-29 (.608)
Over this period, no other NL club is playing anywhere close to these levels. Since the end of May, the Mets are fourth with a .542 winning percentage. Two American League clubs, Toronto and Kansas City, have also played over .600 baseball since May 31, but their potential as postseason opponents will not be witnessed again on a firsthand basis by any of these NL crews until late October.
There weren't a lot of people who saw this arrangement coming. Prior to the season, many observers conceded not only the NL pennant, but the World Series championship to the Nationals. At this point, the Nats would have to catch fire just to reach the postseason. Yes, they've had injuries to key personnel, but so have the Cardinals, the club with baseball's best record.
Many people liked the Dodgers because of their combination of star power and seemingly limitless resources. They currently have a slim lead over the Giants in the NL West. But at this point, the second-place finisher in that division would not qualify as a Wild Card entrant.
The Cardinals' success could have been predicted. They have reached the NL Championship Series in each of the last four years, and in two of those seasons they advanced to the World Series. What couldn't have been predicted was the Redbirds maintaining baseball's best record while losing their ace, one of their primary setup men, their first baseman and an entire outfield to injury.
With terrific pitching combined with a midrange offense, the Cardinals have to win close, low-scoring games. And they do.
After taking two out of three from the Giants last week in a series in which each team scored a total of six runs, Cardinals manager Mike Matheny said: "It's been that way all year, it doesn't matter whether it's the Giants or anybody else. We knew that this was a team that was going to come in and they were going to compete. That's going to be the way it is, that's the kind of games we play.
"Let's dig in and do what we have to do and not flinch. I think it's kind of been a part of our club's makeup. Trying to find a way to make it happen a way to define our team, trying to find a way to win. I think it's a great attitude to have and a great statement to make about a team."
The Pirates shouldn't be much of a shock, either. They are headed toward their third straight postseason appearance. Since May 31, they have the best record in the Majors.
They are a genuinely talented team and, managed by Clint Hurdle, a tough-minded team, as well. Andrew McCutchen is one of the most dynamic players in the game, and Gerrit Cole has earned a spot among the elite starters. The real question with the Bucs is not whether they can qualify for the postseason, but whether they can overtake the Cardinals and win the division.
The Cubs, meanwhile, with their impressive core of prospects busily turning potential into production, were a question of when, not if. And apparently the "when" is a lot sooner than many people thought.
With all the young talent taking strides and making a difference, with manager Joe Maddon's relentless but thoughtful positivity and with Jake Arrieta emerging as a genuine frontline starter, there is absolutely nothing fluky about their performance.
How good are they? While the Cubs are third in the NL Central, their record would make them first in four of the other five divisions. They would trail the Kansas City Royals, just as the rest of the AL does.
In September, as good as these clubs have been, there may be no coasting home. These three clubs will play each other six times each. The hope for other Wild Card contenders must be that this competitive combination would spell trouble for at least one NL Central contender. But with more than 75 percent of the season in the books, the Cardinals, Pirates and Cubs have displayed no recent signs of wilting, folding or even noticeably slumping.