When I looked at the Cubs at the beginning of the season, one of the most notable aspects of the team was their depth. They were projected to have six position players in the top ten at their positions, as well as one of the best starting rotations and bullpens in the league.

Overall, the season has obviously gone well; they've got baseball's best winning percentage at .707, almost 100 points better than the Nationals and Rangers. They're scoring the third-most runs per game in baseball. They're giving up the fewest runs per game in the majors, the only team giving up fewer than three runs a game. Fangraphs projects them to win 102 games; Baseball Prospectus, 101. At their current pace, they'd win 115 games—one shy of the Seattle Mariners' 2001 season, when they won 116 games with a .714 winning percentage—the best record in the modern era.

And depth is a big reason why. To look at how that aspect of the team was working, I started with the cumulative wins above replacement for every position on every team, using data from Fangraphs. That includes all players who've played at those positions; part of the Cubs' design is having multi-position players like Ben Zobrist who can be moved around to take advantage of matchups and account for injuries or rest.

Once I had that, I ranked how good each team has been at each position so far, and then took the average of that rank. The lower the average, the more likely a team is to be better than others across the board.

And the Cubs are good across the board, as expected.

Team Average Positional Rank by WAR
1. Cubs 7.9
2. Red Sox 9.7
3. Giants 11.3
25. White Sox 18.3
30.Braves 23.4

But, of course, it hasn't worked specifically as expected. Here's how the Cubs rank at each position, out of 30 MLB teams.

Cubs WAR Rankings by Position

Starting pitching
Relief pitching
First base
Second base
Third base
Left field
Center field
Right field
Source: Fangraphs

There are surprises, both ways. Right field has been a weakness, as Jason Heyward is hitting a mere .220/.317/.309. Heyward has started slow before (he's a career .225 hitter in March/April and .245 in May), but his start has been borderline worrisome. At the beginning of May, Jeff Sullivan noticed that Heyward had been hitting balls softly more often and hitting them hard less often, and that hasn't improved.

Of course, Heyward's other skills mean that, even hitting as poorly as he is, he's still not terrible—by Fangraphs's measures, he's the third-best defensive right fielder in 2016 and the second-best baserunner at that position. Overall, they have him ranked as the 17th-best right fielder at a deep position.

Which isn't great, but if that's your worst player, that's not bad. Every other team in baseball has a lower rank for at least one position.

Fortunately, Dexter Fowler was not expected to be one of the better centerfielders in baseball; instead, he's been the second-best, just barely behind Mike Trout. He's already racked up as many WAR as he did last year, and last year was considered a positive surprise. He's inevitably fallen off an unsustainable pace, hitting .347 in March/April, .295 in May, and .240 so far in June, but the Cubs have already banked as much value from him as they got all of last year, and there's still hope Heyward could pick up the slack, as Fowler has picked up Heyward's so far.

The other big surprise is the bullpen, which requires some explaining. It might not seem like the Cubs have had a mediocre bullpen; they have the seventh-best ERA in baseball. But Fangraphs uses fielding-independent pitching in order to tease out the underlying performance, trying to account for luck. And in that the Cubs rank 20th. Opposing teams have a .245 batting average on balls in play against the bullpen, which is freakishly low.

Only one team's bullpen has had a BABIP that low, over a full season, since 2000—the 2001 Mariners.

That's one thing Rany Jazayerli picks up on in his overview of the team:

If their team BABIP has been the beneficiary of good luck and starts to regress to the mean, they may cool off to the point of finishing the season as just an ordinary great team (by which we mean they’ll still probably win more than 100 games, the first Cubs team to do that since 1910). But if they can continue to turn balls in play into outs three-quarters of the time, then their run prevention may not be a fluke, and they may in fact make a serious challenge for 116 wins.

The Cubs' pitchers, as a whole, have a .249 BABIP. The best BABIP since 2000? The 2001 Mariners, at .260. If they're going to challenge that team, they'll need some of their luck, too.

In other Cubs news: The team has suffered one big loss recently—the pseudonymous consultant Tom Tango, a legendary stats analyst who created some of the best-known advanced statistics and who was part of the team's impressive stat squad we highlighted at the beginning of the season.

But the Cubs' loss is the general fan community's gain. Tango is moving to MLB Advanced Media as their "senior database architect of stats." They are the keepers of Statcast data, the new, highly complex, and still mysterious system that tracks things like a player's route efficiency and speed in chasing down a ball, a pitcher's release point and perceived velocity, the spin rate of pitches, and more fine-grained data.

What does this mean? Hopefully that Tango, a legend among independent stats analysts, will be instrumental in developing new metrics and releasing them to the public—maybe even with the underlying data. If you read between the lines of his interview with Dave Cameron, it's not an unreasonable expectation. So in the next couple or few years, the tools to figure out where the Cubs are going could be even more powerful.