The Chicago Cubs have won 387 games in the past four years, more than any other team in baseball. The team made three straight NLCS appearances between 2015-17. And in 2016, the Cubs snapped a 108-year title drought.

But despite winning 95 games in 2018, the Cubs withered in September, going 16-12 and losing two crucial series' in Milwaukee and Washington before losing the NL Central tiebreaker to the Brewers in Game 163.

The tenuous feeling of a collapse and consistent offensive ineptitude caught up to the Cubs in the NL Wild Card game, as they would fall to the Colorado Rockies in extra innings.

Chicago finished the season with the second-highest total of games scoring just one run or fewer, right behind the Baltimore Orioles. Yes, the same Orioles team that went 47-115 last year.

With Theo Epstein preaching accountability and Joe Maddon on a lame-duck contract, there is a must-win aura that surrounds the 2019 Cubs.

Here are five x-factor players that will determine Chicago's success this season.

Brandon Morrow, Cubs

5. Brandon Morrow

Morrow continued Chicago's streak of establishing a dominant closer at the back of the bullpen, following in the footsteps of Aroldis Chapman and Wade Davis.

In his first season with the Cubs, Morrow notched 22 saves before the All-Star Break, posting a 1.47 ERA and 295 ERA+ for good measure.

Unfortunately, Morrow would not pitch in a single game in the second half. He was placed on the disabled list and eventually shut down in September, succumbing to elbow issues.

Morrow had surgery on the throwing elbow in November, but he will still miss all of April. How he progresses could have a massive impact on the Chicago bullpen, which looked shaky at the end of last season due to overuse of guys like Steve Cishek.

The Cubs have added Brad Brach and other non-roster players to look to bolster their bullpen in Morrow's absence, but a healthy Morrow would instantly galvanize the unit.

Albert Almora, Cubs

4. Albert Almora

Realistically, the argument could be made for any of the Cubs outfielders–including Kyle Schwarber, Ian Happ, and Jason Heyward–as x-factors. But we're going with Almora.

Almora seemingly established himself as the everyday center fielder early in 2018. On top of playing elite defense, Almora slashed .319/.357/.438 and racked up 276 at-bats in the first half.

In the second half? Well, it was a different story. The 24-year-old slashed .232/.267/.280 in over 100 fewer at-bats, as Joe Maddon began to platoon Almora more regularly with (especially) Happ and Schwarber.

Some have blamed Maddon for Almora's second-half struggles. After all, he hit .333 in nearly 200 at-bats at the leadoff spot, where the Cubs have sorely lacked production since the days of Dexter Fowler.

However, Maddon told ESPN's Jesse Rogers that he will continue to platoon his outfielders in 2019.

Can Almora instill more confidence in Maddon by drawing more walks and finding more ways to get on base? The numbers do not lie. When Almora leads off, he can be a spark plug.

But more than anything, the Cubs need more steadiness from Almora at the dish, especially because of his defensive talents.

Willson Contreras, Cubs

3. Willson Contreras

By the end of the 2017 season, Contreras had become arguably the best catcher in the National League after clubbing 21 home runs with a .855 OPS.

And much like Almora, the early returns were good last season. Contreras was voted as the starter in the All-Star Game and although not on pace for the numbers he posted in the year prior, he was still producing.

But Contreras fell off a cliff in the second half, hitting just three homers and tallying a woeful .585 OPS. Along with Kris Bryant–more on that later–Contreras' struggles were perhaps the most consequential to Chicago's lack of offensive firepower down the stretch.

Contreras caught the highest number of innings in the bigs last year (1,109.2), so it is possible that he simply ran out of gas.

However, his workload is mostly on par with other catchers his age. So, how will he adapt? Or will the Cubs find a more defensive-minded backup catcher (because Victor Caratini will not cut it) that can spare Contreras innings?

These questions will loom large all season long.

Yu Darvish, Cubs

2. Yu Darvish

This one is rather obvious. After signing a six-year, $126 million deal with the Cubs last offseason, Darvish made just eight starts in 2018.

They weren't good either, as Darvish posted a 4.95 ERA and 4.7 BB/9 in those eight appearances.

A frequent focus during Spring Training, Darvish has apparently made significant strides since undergoing elbow surgery in September.

When he is at his best, Darvish is electric. He still possesses the stuff akin to that of the game's most dominant pitchers. His K/9 is always an encouraging peripheral in this respect.

But Darvish is also 32 and has now had multiple surgeries on his throwing elbow. Will he really be able to stay healthy?

A rebound season from Darvish would go a long way in determining whether or not the Cubs can reclaim the NL Central crown.

Kris Bryant, Cubs

1. Kris Bryant

Another shoe-in here. But it holds water.

Bryant just wasn't the same after hurting his shoulder in May. His batting average dropped by over 30 points the rest of the way, while his slugging percentage also plummeted.

The former MVP struck out in nearly one-third of his plate appearances in September. He hit just 13 homers. The list goes on…

What would a healthy Bryant have meant to the 2018 Cubs? We may never know, but we are about to find out how important he is to the offense this season.

With launch angle disciple Anthony Iapoce replacing Chili Davis as the new hitting coach, Bryant will get back to basics.

Another MVP-caliber season could help restore order in Chicago.