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“You can’t win the pennant in the first month of the season, but you can lose it.” We’ve heard that axiom a million times, but by God the Chicago Cubs were out to prove it wrong. By close of business on May 8, the Cubbies were 27-12, having just wrapped up their second discrete 10-game winning streak of the season.

Our preseason playoff odds had the Cubs, Pirates, and Brewers in a close three-way fight for the NL Central, all with odds between 24.3% and 35.6%. The Reds and Cardinals were in the single digits, but by no means without hope. Chicago’s odds of winning the division peaked on May 7 at 63.4% — a mighty statement in a division expected to be competitive.

But shouldn’t it have been higher? The Braves got off to just as hot a start, and their odds for winning the division have been in the 80s since the last week of April. The Yankees’ division-winning odds peaked around the same time as Chicago’s, but about 20 points higher.

Even when they were only losing once every two weeks, the Cubs’ lead in the Central never grew beyond 3 1/2 games. And as dominant as Chicago was over the first 39 games of the season, only eight of those games came against intradivisional competition — and the Cubs only went 5-3 in those games.

That meant that when the Cubs were pummeling all comers into the dirt, they weren’t inflicting direct damage upon their competitors… and suffice it to say, that fluke of the schedule has come back to haunt them in a big way.

Since May 9, Chicago is 5-16, including a 10-game losing streak. Since the end of that run, the Cubs have slowed their descent but not arrested it, splitting a four-gamer against the Pirates last week and dropping two of three in St. Louis over the weekend. Add in a three-game sweep by Milwaukee during that losing streak, and the Cubs are now 3-8 against NL Central opposition since their high-water mark. That leaves them at 32-28, with a 13.4% chance of winning the division. And because everyone in said division is over .500 at the moment, the Cubs are now 5 1/2 games out of first place and only 1 1/2 out of the cellar.

Unfortunately for the Cubs, this is neither an industry nor a society in which I can blog about what a shame this is, and how we should all have empathy for this group of guys that looked like the World Series favorite one day and all of a sudden started putting their pants on backwards. And while conceding the broader point that a 10-game losing streak is inherently an all-hands effort, we need someone to blame:

Yeah, that’s pretty damning, isn’t it? The Cubs’ pitching staff is worse overall over the past three weeks than it was during the hot streak, but not by a massive margin. The offense, however, went from literally the best in baseball to the bottom five. As of May 8, the Cubs were scoring 5.51 runs per game, which puts them about on par with the 2001 Mariners and the 2018 Red Sox.

Since then, they’re scoring 3.29 runs per game, which is a scoring rate comparable to that posted by this year’s Ottawa Senators. I regret having to make a cross-sport comparison, but there is no team in major league history that’s scored so infrequently over a full season. At the same time, the Cubs’ wRC+ has dropped from 123 to 79. Last season, Manny Machado and Seiya Suzuki had wRC+ marks of 123, and Kyle Isbel and Daniel Schneemann had 79s. Which really paints a picture.

Mike Petriello of MLB.com had an interesting insight as to what’s happened to the Cubs’ offense over this cold streak: Opposing pitchers have been making them smoke the whole pack of breaking balls in one sitting.

The Cubs account for five of the 10 hitters with the highest breaking ball percentages in the month of May. As a team, the Cubs saw 37% breaking balls last month, which is one of the highest percentages for any team on record.

That’s not a perfect proxy for this slump; the Cubs won the first eight games they played in May, and scored 46 runs along the way. And Mike points out in his post that they actually hit spin quite well in April; I’m not convinced this is a weakness specific to the Cubs.

But it is a weakness almost all hitters share. This season, big league hitters are batting .215 against breaking balls and .261 against fastballs. There’s such a thing as thickening the soup with too much spin, but in general the Cubs have been seeing more pitches that are harder to hit.

And it’s not just getting harder to hit because the Cubs have faced more breaking balls. A big chunk of the Cubs’ run to 27-12 involved taking six of seven from the Phillies in the span of 11 days. The Phillies were in the midst of their own 10-game losing streak at the time, which cost Rob Thomson his job. The Phillies quickly bounced back, maybe because of the managerial change, but also because their run of 13 games against the Cubs and Braves led into a softer part of the schedule.

The Cubs’ schedule over the past three weeks included a trip to Atlanta and a sweep at the hands of the white-hot Brewers, but the teams they’ve faced aren’t as impressive as the individual starting pitchers.

Over the past 21 games, the Cubs have faced four of the top 10 (Jacob Misiorowski, Davis Martin, Braxton Ashcraft, and Paul Skenes) and seven of the top 25 (those three, plus Kyle Harrison, Chris Sale, and Sean Burke) pitchers on the league-wide WAR leaderboard. Plus Jacob deGrom and Spencer Arrighetti, whose 1.34 ERA is second best in the league among pitchers with at least 40 innings.

Five of those nine pitchers blanked the Cubs; another three allowed a single earned run. Collectively, they held the Cubs to a 1.19 ERA and 69 strikeouts against 56 total baserunners in 53 innings. The Cubs went 3-6 in those games.

Which, as you already know if you can subtract, means they went 2-10 in the other 12.

How did that happen?

Well, I mentioned earlier that while the Cubs’ offense had gone totally in the crapper, the pitching hadn’t quite had as rough a go of it. The team-wide ERA dropped from eighth in the league to 27th after the May 8 cutoff, but if you’re looking at FIP and xERA, it’s a difference of less than a run — totally within normal variation for a team over three weeks.

But looking at Chicago’s pitching staff holistically simplifies and obscures the problem. When a good team faceplants as badly as the Cubs have, the first place I usually look is the bullpen. That’s where the margins are finest. If one high-leverage reliever has a bad cold or finds out his girlfriend cheated on him, that could turn two games a week, and make a 100-win team look like a 60-win team over a small sample.

The Cubs’ bullpen, however, has actually been a little better after the high-water mark than before. Phil Maton’s had a couple rough high-leverage appearances with the game tied or the Cubs trailing, but as a staff, they’ve only blown one save out of these 16 losses. This was an OK bullpen before, and it’s an OK bullpen now.

The real problem is in the rotation:

The Cubs have a case that they’ve been bit by the injury bug; I’d argue that the team’s top four starting pitchers — Matthew Boyd, Cade Horton, Justin Steele, and Edward Cabrera — are all on the IL right now. But Horton and Steele (who’s been out since last April) were already injured long before all this happened. And while Boyd’s meniscus went on sabbatical at the exact moment the Cubs’ fortunes turned, the Cubs had only won two of their previous 11 games when Cabrera got hurt.

Whatever the reason, the Cubs’ rotation has put the offense at a disadvantage it hasn’t been able to overcome. In 10 of their past 21 games, the starter facing the Cubs has thrown at least five innings while allowing, at most, one earned run. Lower the innings threshold to four, and you can make it 13 out of 21.

Over that same span, the Cubs have just three starts of five innings and zero or one earned runs, and just one additional scoreless start of four innings. On seven occasions, the Cubs’ starter allowed more earned runs than he completed innings. On the rare occasions that the Cubs’ starter does pitch well, the offense doesn’t give him any run support.

On Saturday, the Cubs put it all together for a 6-1 win over the Cardinals. Ben Brown threw seven innings and allowed only one run, while striking out six and allowing a walk and three hits. That was the Cubs’ best start, by game score, in the past 21 games.

The Cubs have gotten five other starts with a game score over 55 during this cold streak, including a seven-inning, two-run outing by Shota Imanaga on May 13, and a scoreless four-inning, one-hit, seven-strikeout start from Brown the next day. Over those five games, Cubs starters allowed a 1.98 ERA and a .237 opponent OBP — these are games they should be winning easily.

They went 1-4 in those five games, scoring a total of four runs along the way.

How does a team go from a 112-win pace on May 8 to the verge of the cellar on June 1? The offense goes from the best in the league to among the worst. The starting rotation suffers two key injuries and gets almost nothing out of its healthy pitchers, and when said pitchers do perform well, the ice-cold offense no-shows.

But the Cubs’ defense is still the best in baseball and the bullpen has been mostly fine. So, you know, it could be worse.