If 2016 was about overcoming curses for the Chicago Cubs, 2017 has been about overcoming adversity.

Their starting rotation wobbled like a Ferrari with a flat, forcing president of baseball operations Theo Epstein to jettison top prospects in a trade for left-hander Jose Quintana. Key offensive cogs—including outfielder Kyle Schwarber and super-utilityman Ben Zobrist—have struggled.

Now, their burgeoning franchise catcher is out with a strained hamstring.

The injury, which Contreras suffered on the basepaths Aug. 9, could shelve him four to six weeks, per Jesse Rogers of ESPN Chicago.

The Cubbies have a tenuous hold on first place in the National League Central at 62-55, 1.5 games up on the surging St. Louis Cardinals and 2.5 games ahead of the upstart Milwaukee Brewers.

This isn't how the script was supposed to read for the champs.

Prior to his injury, Contreras was slashing .274/.342/.519 with 21 home runs and 70 RBI. He hit .321 in July with a 1.019 OPS and was hitting .361 with a 1.185 OPS in August while flashing his trademark howitzer arm.

"Obviously, he's been carrying us," manager Joe Maddon said, per Patrick Mooney of CSN Chicago. "Any kind of offensive resurgence we've had has been primarily centered around him and his contributions. And then his versatility—he can pick you up at first base. He can pick you up in the outfield. All the different things that he does—his energy—all that stuff is vital to us."

Steve Rosenbloom of the Chicago Tribune captured the gut reaction of Cubs nation when he wrote, "...the first response to Willson Contreras' hamstring injury is to go all Chicken Little. The sky is falling. The dream of a back-to-back World Series titles is dead. Tip your waitstaff and drive home safely, everybody."

That's a tad dramatic. Veteran backstop Alex Avila, acquired at the trade deadline from the Detroit Tigers, owns an .856 OPS between the Motor City and the North Side and is a better pitch-framer than Contreras, per StatCorner. The Cubbies can also turn to rookie Victor Caratini.

Oh, and they've gone 3-1 since Contreras' hammy went haywire, outscoring opponents 32-16 in the process.

"Vic is a great catcher. Avila is a great catcher as well who is very experienced and has learned how to catch the arms we have in a short time span," right-hander Jake Arrieta said, per the Chicago Tribune's Mark Gonzales. "I think we're capable of holding down the fort..."

General manager Jed Hoyer added, per Mooney: "We're glad we acquired Alex at the deadline. That helps lessen the blow of Willson's injury a lot. Obviously, he was basically platooning for Detroit and catching a lot. He'll continue to do that here."

Still, the loss of Contreras peels another layer off the Cubs' veneer of invincibility. They came into the season as a juggernaut, coated in champagne and confetti and the air of dynastic inevitability. 

Now, they're struggling to win their division, let alone challenge the mighty Los Angeles Dodgers and Washington Nationals for NL supremacy. 

Unless Contreras returns ahead of schedule, he will miss most of the remaining regular season.

The Cubs play Game 162 on Oct. 1. If Contreras comes back on the early end of his timeline, he will have roughly three weeks to get ready for the postseason. 

If he suffers any setbacks, the 25-year-old could be getting his legs under him in the division series, assuming Chicago makes it that far.

It's no guarantee.

FanGraphs gives the Cubs an 80.7 percent chance of winning the Central and an 87.6 percent chance of snagging a wild-card slot at least. 

Despite their recent feline-aided run, the Cards are flawed, and it appears the bloom is off the Brewers' rose for now.

The issues keep piling up for the Cubs, though, and merely sneaking into the postseason isn't adequate. After burying the billy goat last year, it's another Commissioner's Trophy or bust.

A healthy, productive Contreras brings them closer to the trophy.

His absence nudges them in the direction of bust. 

All statistics current as of Monday and courtesy of MLB.com and Baseball-Reference unless otherwise noted.