In addition to being one of the great sports stories of the 21st century — breaking a 108-year championship drought in extra innings of World Series Game 7 — the 2016 Chicago Cubs were legitimately one of the best baseball teams of all time. With a championship core of young talent that included Kris Bryant (age 24), Anthony Rizzo (26), Kyle Hendricks (26), Addison Russell (22), Javier Baez (23), Kyle Schwarber (23), Willson Contreras (24) and Jason Heyward (26), Chicago seemed poised to follow up that magical run by becoming a dynasty in the coming seasons.

That’s not quite how things have played out. The 2017 Cubs stumbled out of the gate and never quite clicked, eventually losing to the Dodgers in the National League Championship Series. The 2018 version squandered the five-game division lead they held over the Brewers on Sept. 1, lost the division tiebreaker in Game 163 of the regular season and then promptly lost the wild-card game against Colorado. And the Cubs’ grip on the Central figures to loosen even further this season. According to a preliminary version of our 2019 MLB Projections, we give Chicago only the third-best projected record (84 wins) in the division, with a mere 24 percent chance of winning it.

The NL Central has caught up with the Cubs How our preliminary Elo ratings are forecasting the 2019 NL Central race Avg. Simulated Season Chance to… Team Elo Rating Wins Losses Run Diff. Make Playoffs Win Division Win World Series Cardinals 1528 86 76 +42 45% 28% 4% Brewers 1525 85 77 +33 41 25 4 Cubs 1523 84 78 +31 40 24 4 Pirates 1502 79 83 -15 25 13 1 Reds 1497 77 85 -32 20 10 1 Based on 100,000 simulations of the 2019 MLB season. Sources: Baseball prospectus, Fangraphs, Clay Davenport, Caesar’s Palace

How is it possible that the Cubs went from dynasty in the making in 2016 to a team struggling to stay atop its own division in less than three years? The answer lies in part with the team’s declining core and team president Theo Epstein’s inability to supplement it with effective reinforcements from the outside — particularly when it comes to pitching.

Few teams have ever undergone an overhaul as extreme as the Cubs did in the four years leading up to their championship season. Chicago improved from 16.6 wins above replacement during their dreadful 61-win 2012 to 56.8 WAR in 2016, with essentially all of those gains coming via newly acquired talent (rather than improvements from existing holdovers). As part of that process, Epstein made a number of shrewd trades, drafted several key contributors and increased Chicago’s payroll by 169 percent relative to the MLB average.

It all came together as a textbook example of tearing down and rebuilding a franchise. The 2016 Cubs had baseball’s third-most-valuable pitchers by WAR (including the No. 1 starting rotation) and the best defense by a country mile, on top of an offense that tied for the NL lead in adjusted on-base plus slugging percentage. The pitching side was expensive and creaky — one of the oldest ever to win a World Series, in fact — but Epstein and the Cubs seemed to be winning the battle of ideas about where to invest in order to build a ballclub with perennial championship aspirations.

Since 2016, though, the formula has broken down. The team’s net WAR on arrivals and departures — in which Chicago topped baseball from 2012 to 2016 — has dropped to eighth-worst in MLB. The Cubs haven’t added very many new faces, and what few acquisitions the team has made have largely flopped, particularly on the mound. Starters Tyler Chatwood, Jose Quintana and Yu Darvish all badly underperformed their established performance levels as members of the Cubs, for instance. As a result, Chicago has mainly had to rely on its existing core to keep the team in contention.

This makes some sense, to a certain extent. The natural maturation process of a championship team is to add talent in the lead-up to contention, then shift toward maintaining it once the roster finally reaches the top of the heap. But that hasn’t really happened, either. Not only have the new players underperformed, the team’s nexus of homegrown talent has, too. The Cubs’ holdovers are a net -14.8 WAR since 2016, which ranks fourth-worst in MLB. The multiyear plan to build a great core and then set it loose doesn’t work when that core regresses.

The rise and stall of the Cubs Chicago Cubs’ net wins above replacement (WAR) added/subtracted by season from incoming/outgoing and existing players, 2013-18 Net WAR from… Season Previous WAR + Arrivals – Departures + Holdovers = Season WAR 2013 16.6 + 10.1 + 2.2 – 2.9 = 26.1 2014 26.1 + 7.8 – 6.1 + 2.2 = 30.0 2015 30.0 + 19.8 – 3.4 – 2.0 = 44.5 2016 44.5 + 10.8 + 0.5 + 1 = 56.8 2017 56.8 + 8.3 – 9.5 – 13.1 = 42.5 2018 42.5 + 7.5 – 6.2 – 1.8 = 42.1 Positive net WAR for departures means departing players cumulatively had negative WAR the previous year. Sources: Baseball-Reference.com, FanGraphs

The 2018 Cubs shared some of the strengths of the 2016 club — both had top-5 defenses by WAR — but Chicago slipped to 14th in WAR from its starting rotation and was basically average offensively according to adjusted OPS. An injury to Bryant cost him 60 games, while Rizzo’s performance declined for reasons mostly unknown.

Bryzzo wasn’t alone in its combined downturn. Sixteen players appeared on the 2016, 2017 and 2018 Cubs. Some of them — such as Contreras, Baez and Schwarber — have flourished in expanded roles since 2016. But in more cases than not, this core group has produced less despite being asked to carry more of the load over time:

The Cubs are relying on the same core … and getting less For players who were on the 2016, 2017 and 2018 Chicago Cubs, share of team playing time logged* and wins above replacement (WAR) by season Playing time WAR Player Pos 2016 2017 2018 2016 2017 2018 Anthony Rizzo 1B 6.6% 6.8% 6.4% 5.2 4.2 2.8 Kris Bryant 3B 6.8 6.5 4.4 7.6 6.4 2.1 Ben Zobrist 2B 6.2 4.8 5.0 3.8 0.4 3.4 Jon Lester P 5.7 5.1 4.9 4.9 2.0 2.4 Javier Baez IF 4.4 5.0 6.2 2.7 2.6 5.7 Jason Heyward RF 5.8 4.7 4.7 1.1 1.6 1.8 Kyle Hendricks P 5.3 4.0 5.4 4.8 2.8 3.0 Addison Russell SS 5.8 3.8 4.5 3.7 1.9 1.7 Willson Contreras C 2.8 4.2 5.2 1.9 3.6 2.7 Kyle Schwarber LF 0.0 4.8 4.9 -0.1 0.8 2.3 Albert Almora CF 1.1 3.2 4.6 0.6 1.1 1.4 Mike Montgomery P 1.0 3.8 3.1 0.2 1.9 1.2 Pedro Strop P 1.5 2.1 2.2 0.8 1.0 1.4 Carl Edwards Jr. P 1.1 2.4 1.8 0.4 1.2 1.2 Tommy La Stella IF 1.7 1.5 1.8 0.6 0.5 0.1 Rob Zastryzny P 0.5 0.3 0.2 0.5 -0.2 0.0 Total 56.3 63.0 65.3 38.7 31.8 33.2 * Through plate appearances or (leverage-adjusted) innings pitched. Sources: Baseball-Reference.com, Fangraphs

It also bears mentioning that Epstein and the Cubs have been hamstrung in how much outside talent they can add by a massive payroll bill, which has affected the team’s depth all across the diamond. In terms of marginal payroll per WAR, Chicago went from being the second-most cost-effective playoff team of 2016 to the least cost-effective playoff team of 2018.

Trade pickup Cole Hamels was one of the few pitchers who didn’t underwhelm in Chicago (he was very good upon joining the Cubs at last year’s deadline). And in the field, rookie David Bote was a pleasant surprise last season. Both will be back for 2019, along with practically all the rest of the aforementioned core. The Cubs were briefly rumored to be in on the Bryce Harper derby, but for now Chicago’s biggest offseason acquisition is utilityman Daniel Descalso. And the lack of upgrades is part of the problem heading into 2019.

Although FanGraphs projects the Cubs to have a top-5 lineup, the site sees the pitching staff dropping outside MLB’s top 10 — and with an 88-win prediction for the Cubs, FanGraphs is one of the forecasters most bullish on Chicago’s chances. If the Brewers caught the Cubs on talent last season, the Cardinals might have passed them both by now. Meanwhile, manager Joe Maddon is in the final year of his contract, with no extension in place going forward. From team leadership to the core of the roster, many of the factors that played a key role in Chicago’s rise now look shockingly uncertain three years later.

The good news for Chicago, though, is that the potential still exists for an exciting summer at Wrigley Field. Even if 2016 was an outlier, a team as talented as the 2017 and 2018 Cubs — which was, after all, good enough for an average of 93.5 wins per season — remains a contender. It might not be the kind of dynasty that either Epstein or fans on the North Side had in mind when they were celebrating their curse-breaking World Series victory. But hey, at least it’s far better than all the bad Cub teams of the 1980s and ’90s that many of us grew up watching on WGN.

Jay Boice contributed research.