The National League Central Is Making Sense Again

After trailing the Brewers for much of the season, Anthony Rizzo and the Chicago Cubs have stormed out of the gates in the second half and now lead their division.

It took a lot longer than we thought, but the National League Central is finally starting to conform to preseason expectations.

After spending most of the year looking up at the surprising Milwaukee Brewers, the Chicago Cubs have taken over first place, with 2.5 games separating the two clubs. Judging from the FanGraphs' playoff odds, though, that basically seemed inevitable.

Check out how the division title odds have changed throughout the 2017 season.

The Cubs’ chances never fell below 50.0%, bottoming out at 53.1% on July 10th when they trailed Milwaukee by 5 ½ games. They are now overwhelming favorites within the division -- our models give Chicago an 81.4% chance of winning the division, compared to just 10.2% and 7.6% for the St. Louis Cardinals and Brewers, respectively.

If we contrast that chart with the actual to-date win totals for each NL Central club, we can see a disparity in how little stock the projection models put into Milwaukee's hot start. The Brewers' 56-52 record heading into action on Wednesday is in line with their PythagenPat (56-52) and BaseRuns-implied (54-54) records.

However, based on the track records of the players on their roster, the computers do not see this level of underlying performance continuing. We have them going 26-28 the rest of the way.

What a Difference Three Weeks Makes

For much of the season, the opposite was the case for the Cubs: their record and underlying performance metrics were considerably worse than what we expected. This was a team that returned most of the key components from a World Series team that posted the ninth-best run differential since Integration (plus-252).

At the All-Star break, though, Chicago's run differential stood at zero -- they socred 399 runs and allowed 399 runs. Milwaukee was plus-45 at the time, with a 54.8% Pythagorean winning percentage that was fourth in the National League.

If the only data we had was 2017 statistics, the Brewers would have been considerable favorites to win the Central at this point. They had played better than Chicago and had a 5.5-game advantage. According to FanGraphs' season-to-date playoff odds, Milwaukee would have had a 62.5% chance of winning the division if 2017 performance was the only factor (the Cubs were at 11.3%, behind the Cardinals who had a 18.2% chance in season-to-date only mode).

Of course, the 2017 season does not exist in a vacuum, and projection models take this into account by factoring in larger bodies of work. Contrary to their levels of production in the first half, Travis Shaw is not pegged as a 6.0-WAR player, nor is Eric Thames projected to be the second coming of Barry Bonds.

In the first half, the Brewers’ non-pitchers tied for 10th in wRC+ (104), but they've posted just a 77 wRC+ since the break (only Boston has been worse). Their pitching staff’s decline has been less dramatic -- their ERA- has dropped from 92 in the first half to 104 since the break, this seems mostly BABIP-related (their FIP- has only fallen from 97 to 101 and their strikeout-minus-walk rate has actually increased).

While Milwaukee probably was not as good as their first-half performance indicated, they're certainly not as bad as their second-half record. The Brewers have gone 6-11 with a 36.4% Pythagorean winning percentage since the break. And as mentioned earlier, we project the Brewers’ true talent level to be a tick under .500.

Unfortunately for them, this late July swoon may have put them out of postseason contention, as their overall playoff odds are now just 18.2%. It appears they're definitely out of the running to compete for a division title since we've seen a combination of the Brewers underachieving since the All-Star break and the Cubs dramatically overachieving.

Chicago has won 14 of their 17 games in the second half, while posting a 76.5% Pythagorean winning percentage. The Cubs are not this good (we have them going 32-25 the rest of the way), but by all indications, they are better than the Brewers and have now erased Milwaukee’s hot start.

This clearly looks like Chicago’s race to lose. Just like we thought back at the beginning of the year.