What could go wrong for the Cubs in 2018?

“What could possibly go wrong?”

These days, that phrase is used ironically to describe poor decisions. But sometimes, even good decisions lead to bad results. Pinch-hitting for a relief pitcher, down one, with the bases loaded and one out in the ninth. If the pinch hitter grounds into a game-ending double play, that doesn’t make it a bad decision. But your team still didn’t win the game.

So it goes with the 2018 Cubs. They’ve made a series of good decisions over the past winter. They let pitchers Jake Arrieta, John Lackey and Wade Davis walk and brought in Yu Darvish, Tyler Chatwood and Brandon Morrow. The Cubs let fourth outfielder Jon Jay leave, confident that Albert Almora Jr. and Ian Happ could handle outfield duties. The front office made a big move for Jose Quintana last summer, giving up one of the best prospects in baseball.

They were good moves. It should work. It might not.

Cubs fans are spoiled after reaching the National League Championship Series the past three seasons and winning one World Series title. While they are realistic enough to understand that no team can count on winning several World Series titles in a row anymore, it is a realistic expectation that the Cubs win the N.L. Central year-in and year-out for the foreseeable future. The team is young, talented and quite frankly, just better than every other team in the N.L. Central. They should win the division title this year and they have a good chance of making a deep run in the playoffs and even winning another World Series.

They might not even make the playoffs. That’s how baseball works.

These are some ways that the Cubs could fail to win the N.L. Central in 2018. I’m leaving out stuff like “An asteroid destroys Wrigley Field.” All of these have a reasonable chance of happening. The Cubs “only” won 92 games last season and trailed the Brewers by 5½ games in July. Things got a lot better in the second half and the Cubs reclaimed their N.L. Central title. But anyone who watched the first half last year knows that the team can underachieve.

The Fangraphs projections for the N.L. Central are:

CUBS 94-68
Cardinals 87-75
Brewers 78-84
Pirates 75-87
Reds 72-90

So that’s the Cubs winning the Central by seven games. According to Fangraphs, the Cubs are projected to tie the Dodgers for the best record in the National League. Other projection systems have slightly different numbers, but they all agree that the Cubs should comfortably win the division and should host the first round of the playoffs against either a Wild Card team or the Nationals, who are projected to win the NL East.

So how could the Cubs blow a seven-game advantage? It’s going to take a combination of bad luck and underperformance, but it is possible. Here’s how.

Injuries to starting pitching: Anyone of a certain age can remember the 1985 Cubs, who were favored to repeat their 1984 title until all five starting pitchers ended up on the disabled list at the same time. While no one should expect all five Cubs starters to get injured, some of them certainly could.

Both Jose Quintana and Yu Darvish are projected by Fangraphs to post a WAR of between 4 and 5. If one of those pitchers got injured, that’s half of the Cubs cushion right there. If both of them got hurt, the lead over the Cardinals could be gone completely.

Why this won’t happen: In subtracting a player’s WAR from the Cubs team total, we’re assuming that the player will be replaced by a theoretical replacement-level player, whom, for the sake of argument, we’ll give the totally made-up name of “Eddie Butler.” But it’s not guaranteed that “Butler” will take the innings lost from one of those starting pitchers. Mike Montgomery would likely get the first chance at starts, and he could easily be a 1-2 WAR player in the rotation. There’s also potential rookies like Jen-Ho Tseng or Adbert Alzolay who could step up and mitigate the damage from any injuries.

Also, the Cubs starting pitching staff is neither young nor old. Young pitchers tend to get hurt more because . . .well, we don’t really know but we think it’s either because their bodies are still developing or they just haven’t demonstrated that their bodies can handle the stress. Older pitchers get hurt because they’re old. Every Cubs starter is between 28 and 34 years old, which is the nice sweet spot in maintaining health. Darvish and Chatwood are a risk because they’ve already had one Tommy John surgery, but both are more than two years removed from their surgery and have handled heavy workloads since then. The other three have had clean injury histories, at least by pitcher standards.

Cubs starters could underperform: Noticing a theme here? A lot of the Cubs 2018 season is riding on the performance of their starters. Some of them could be healthy, but just not very good. Jon Lester was certainly showing some signs of age last season with a drop in fastball velocity. Kyle Hendricks has always outperformed his underlying metrics: what if that is no longer true in 2018? Darvish got hammered in the World Series, supposedly because he was tipping his pitches. If that was a sign to come, then the Cubs made an expensive mistake.

Why this won’t happen: It certainly could happen to one of these pitchers. But the odds of it happening to three or four is pretty unlikely. And then you’d also have to count out Montgomery and the others from stepping up into the void. Even if you take one WAR off each Cubs starter, they are still projected to be two games better than the Cardinals.

The bullpen: The Cubs took a risk by letting Wade Davis go to Colorado and replacing him in the back of the bullpen with Brandon Morrow, who was very good last season but is new to relief pitching and has never been a closer before. The Cubs bullpen was certainly a team weakness at the end of the year last year and it’s possible that was something more than just fatigue. Justin Wilson was a major disappointment after coming over from the Tigers.

Why this won’t happen: It could happen, but you have to wonder how much damage it would cause. If Morrow ends up unable to handle closing duties, then other pitchers could step into the void. There will likely be many relievers, including some closers, available on the trade market at reasonable prices this summer. If the Cubs bullpen underperforms, it’s hard to see how it will cost them seven games without the team addressing the problem.

The outfield: I’m not worried about the infield, although an extended loss of catcher Willson Contreras could be a major problem. Otherwise, Anthony Rizzo, Kris Bryant, Addison Russell and Javier Baez are all young and talented and there are excellent backups in Tommy La Stella and Ben Zobrist. Even Ian Happ can play second base.

But the outfield is a bigger issue. Kyle Schwarber‘s new physique is untested. Jason Heyward still provides a ton of value on defense, but if his offense gets any worse, it could be a disaster. Almora was very promising in limited action, but he hasn’t shown that he can consistently hit right-handed pitching yet. Happ is still young and many second-year players fall off from their rookie seasons.

Why this won’t happen: Once again, there is strength in numbers. If Ben Zobrist and Happ count as an outfielders, the Cubs have at least five outfielders who need playing time. Last time I checked, only three play at one time, although who knows what Joe Maddon is up to these days. Still, if you add up the projected WAR of all five outfielders, it only comes to 8.4. It seems pretty unlikely that they’ll lose 80% of their value, especially when there are so many of them. The outfield is likely to be a contributing factor to pitching staff issues, rather than the main cause of any Cubs collapse.

The Cardinals and/or Brewers could be a lot better than expected: This would likely only drop the Cubs to the Wild Card spot rather than costing them the playoffs entirely, but the Cubs could win 94 games and see the Cardinals win 99 and the Brewers 95. We’ve seen this before in 2015, although then it was the Pirates and not the Brewers. If the Cubs finish third in the NL Central, a Wild Card spot could ride on how well the Giants, Rockies and Diamondbacks play out West. (Or even the Phillies and Mets in the East.)

One of the most controversial things in these projection systems is how low they rank the Brewers. Milwaukee won 86 games last year and have added Christian Yelich and Lorenzo Cain, whom Fangraphs project to have a combined WAR of 6.4. So how can an 86 team add six wins and be projected to win 78 games?

Three reasons. One, the systems think the Brewers overachieved last season. Two, the Brewers starting pitching is questionable and their best pitcher, Jimmy Nelson, is going to miss time with a shoulder injury, and shoulder injuries are bad news. Third, Yelich and Cain are not replacing replacement-level players. Yelich is going to take a lot of time from Ryan Braun, who had a WAR of 3.3 last season.

You can make a good case that these projection systems (and Fangraphs aren’t the only won to predict a losing record for Milwaukee) are underestimating the Brewers. But it’s hard to make a case that they are underestimating them by 15 games.

The Cardinals are always the Cardinals. They’re almost never bad. But making up seven games on the Cubs is a tall order. Sure, the Cubs could fall off by three and the Cardinals could overperform by four and that would be in the range of reasonable possibilities. But if you think the Cubs bullpen is shaky, the Cardinals bullpen is positively frightening.

Why this won’t happen: It could happen, but it seems improbable. Again, if the Cardinals or Brewers catch the Cubs, it’s likely going to be more because the Cubs underperform than those two teams overperform, although it will undoubtedly involve some mix of the two.

Could this happen? Yes, the Cubs could fail to win the N.L. Central. They could fail to make the playoffs. It’s going to take a lot of things going wrong. The Cubs seems to have planned for every possible source of failure with a backup plan that should plug the gap enough for the team to keep winning. But no system is foolproof. If the Cubs pitching falls apart and the Brewers (or Cardinals) pitching starts to click, it could be a fierce fight for the playoffs come September.

It could happen. Most likely, the Cubs will claim their third-straight N.L. Central crown this season. After that, it’s pretty impossible to predict. But before Cubs fans can start dreaming about another World Series appearance, they’ll have to get past the rest of the N.L. Central. There are no guarantees.