CHICAGO -- They haven't played their biggest cards yet. But no team has been more aggressively stockpiling pitching this offseason than the Cubs.
The Cubs have rather quietly added eight arms to the 40-man roster since they were beaten by the Dodgers in the National League Championship Series, including at least six who will go to Arizona with a shot at a spot on the Opening Day roster. Chicago has committed $82 million to free agents Tyler Chatwood, Brandon Morrow, Steve Cishek and Drew Smyly. To this point, only the Rockies have invested more in pitching.
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Wade Davis, Bryan Shaw and Jake McGee all received three-year contracts from Colorado, with the deals totaling $106 million. The Cubs are likely to blow past that mark when they identify a replacement for Davis and either re-sign or replace Jacob Arrieta, with Yu Darvish prominently mentioned as a possibility.

The Cubs continue to have conversations with multiple free-agent starters, including Alex Cobb, and are monitoring the availability of controllable starters and closers through trades. That list is believed to include Gerrit Cole, Michael Fulmer, Chris Archer, Jake Odorizzi, Danny Duffy, Danny Salazar, Brad Hand, Roberto Osuna, Alex Colome and Felipe Rivero.
But do the Cubs really have to do anything else?
With Chatwood, Morrow and the others aboard, the Cubs wouldn't be wrong to head into 2018 with the inventory they've accumulated and adjust at midseason, as they've done the last two years. That would add to their flexibility next fall, when Bryce Harper, Manny Machado, Charlie Blackmon, Andrew Miller, A.J. Pollock and Zach Britton could be intriguing free-agent targets (at this point they could be as much as $85 million below the 2019 Competitive Balance Tax threshold of $206 million).

Let's take a look at where the Cubs stand.
They have one of the best rotations in the National League. Kyle Hendricks, Jonathan Lester, Jose Quintana and Chatwood are all under control through at least 2020. Adding Darvish or re-signing Arrieta could give the Cubs' the best rotation going, especially if Chatwood elevates his performance out of Colorado.
Chatwood picked the Cubs over a lot of teams that were interested in taking that bet. Manager Joe Maddon raved about him after he beat the Cubs last June. He comes to the Cubs at about the same age that Arrieta did, and his 4.31 career ERA is a lot better than the one Arrieta brought from Baltimore.

There's a risk to Chatwood, who had Tommy John surgery as a 16-year-old and again in 2014. But he was throwing harder last season (average four-seam fastball 95.2 mph, average sinker 94.8 mph) than at any point in his Major League career and was thoroughly checked out by Cubs doctors before getting his three-year, $38 million contract.

Quintana, acquired from the White Sox over the All-Star break last season, heads into his age-29 season as something of a secret weapon. He was off to an uncharacteristically shaky start last season before compiling a 3.74 ERA in 14 starts with the Cubs.
Quintana's 1.073 career WHIP at Wrigley is the lowest in the rotation. And if you've watched him, you know he's capable of winning 18 games and earning Cy Young Award consideration. He flashed his potential after coming to the Cubs, but his first full year in the NL could be really special.
Mike Montgomery, who will be stretched out as a starter in Spring Training but is expected to start the regular season in the bullpen, is highly motivated to show president of baseball operations Theo Epstein what he can do if he gets 25-30 starts. Smyly, signed more for 2019 than '18, underwent Tommy John surgery last July but could help late in the season.
Don't overlook Jen-Ho Tseng (13-4, 2.54 in 24 starts between Double-A and Triple-A), who was the Cubs' Minor League Pitcher of the Year. He could push for a job with a strong Spring Training. So could Eddie Butler and Alec Mills, who will each be in their second year in the organization.
The Cubs added two ninth-inning options in Morrow and Cishek, but it seems likely they'll add an established closer, most likely in a trade. C.J. Edwards has shown the potential to develop into a closer, but he got banged around in the 2017 postseason, making it likely he'll return to a setup role.

Justin Wilson, Pedro Strop and Justin Grimm will return, with the left-handed Wilson heading into Spring Training as a project for new pitching coach Jim Hickey. Wilson lost track of the strike zone after arriving in a trade with the Tigers and was left off the NL Championship Series roster.
The Cubs are excited about Dario Alvarez, who can be described as sliderific. His fastball-slider combination has allowed him to strike out 11.4 per nine innings in his 56 Major League outings with the Rangers, Braves and Mets, but control has been an issue (14 walks in 16 1/3 innings for Texas last year). His potential earned him a Major League contract as a Minor League free agent.
The Cubs have also added bullpen depth with waiver claims for lefty Randy Rosario and right-handers Luke Farrell (the son of former Red Sox manager John Farrell) and Cory Mazzoni. The 23-year-old Rosario was briefly promoted from Double-A to the Majors with the Twins last year, and has youth on his side.

Farrell (26) is a Northwestern University product who made his Major League debut for the Reds last year, with his dad in attendance. Mazzoni (28), a second-round pick of the Mets from North Carolina State in 2011, pitched for the Padres in 2015 and '17 but was dropped off the 40-man roster.
The Cubs love how Mazzoni looked in Triple-A in the second half of last season (31 strikeouts, three walks in 20 1/3 innings) and hope he can find that groove this spring. He and Farrell will have immediate chances to establish themselves.
Pitching depth can make or break teams in the postseason, and the Cubs are once again searching everywhere to build a championship staff. They probably won't stop now -- but they could. That's saying a lot given the loss of Arrieta, Davis and John Lackey.