The job of a relief pitcher may be the most volatile role in all of sports.
Relievers can come out of absolutely nowhere and turn in incredible seasons. New Cubs closer Brandon Morrow and former White Sox setup guy Anthony Swarzak are two recent examples.
But bullpen arms can also disappear as fast as they arrive. Look at Hector Rondon's precipitous fall in Chicago from elite closer to a guy in the doghouse and out of the circle of trust.
Cubs president of baseball operations Theo Epstein understands this volatility and acknowledges the high level of risk associated with relievers, choosing to combat that risk by taking a bunch of fliers on players.
What relievers could emerge as a diamond in the rough and provide an unexpected lift in the Cubs' 2018 bullpen?
We are not including Dillon Maples on this list, because in a lot of ways, he's already arrived. It would not be crazy to think a kid with a 100 mph fastball, a wipeout slider and the pedigree of a top pitching prospect to make an impact the year after turning in a dominant minor-league season and making his MLB debut. Maples figures to spend time in Chicago at some point in 2018, even if he doesn't make the Opening Day roster.
But here are eight other guys who may come out of nowhere in 2018:
1. Adbert Alzolay, RHP
Alzolay is currently the organization's top starting pitching prospect and the Cubs are already talking about the possibility of him serving as depth for the big-league rotation.
But Alzolay may also find a way to make an impact out of the bullpen. The Cubs will want to limit his innings throughout his age-23 season, so if he forces the issue and deserves a call-up to The Show, maybe he can best help the team as a middle reliever.
Alzolay made seven relief appearances in the Arizona Fall League just a few months ago, striking out 13 batters in 11.2 innings. He has the stuff and the control to get big-league hitters out.
2. Duane Underwood Jr., RHP
The same thing applies to Underwood as Alzolay. Underwood was a former high draft pick (2nd round in 2012) with good stuff and is still only 23. He's struggled with his health in recent years, so there's no way the Cubs will overload him in 2018.
Even if Underwood sticks as a starter long-term, he could provide some value in Chicago out of the bullpen late this year.
3. Shae Simmons, RHP
Simmons has bounced around for a few years after being drafted in 2012, but he's still only 27 and signed a free-agent deal with the Cubs last month.
He comes with some big-league experience and success under his belt, appearing in 26 games with the Atlanta Braves in 2014, posting a 2.91 ERA and 9.6 K/9.
Simmons missed all of 2015 to Tommy John and pitched in just 22 games in 2017 between the majors and minors, but has struck out 231 batters across 177.1 innings and if he can remain healthy, may be an underrated contributor to the Cubs bullpen.
4. Dario Alvarez, LHP
The 29-year-old southpaw was one of the Cubs' first signings this winter (Nov. 29) and also has big-league experience, though with mixed results.
Alvarez has a career 11.4 K/9 rate in 56 MLB games, but also has a 5.06 ERA and 1.63 WHIP. With Triple-A Round Rock in the Texas Rangers system last season, he posted a 2.33 ERA and struck out 36 batters in only 27 innings.
Alvarez will most likely begin the season in the minors and provide left-handed depth in case any of the southpaws (Justin Wilson, Brian Duensing, Mike Montgomery) in Chicago are injured or ineffective.
5. Corey Black, RHP
This name may be familiar to most Cubs fans — he was the main piece in return for Alfonso Soriano from the New York Yankees back in 2013.
Now 26, Black missed all of 2017 with injury. He was moved out of the rotation to the bullpen in the middle of 2015 with Double-A Tennessee and made 48 appearances as a reliever in 2016, 28 of which came with Triple-A Iowa.
Black has strikeout stuff (career 9.5 K/9 in the minors) and whiffed 62 batters in 53 innings in 2016. Now fully healthy, it wouldn't be surprising to see him take a leap and make his MLB debut at some point this summer.
6. Cory Mazzoni, RHP
The Cubs claimed the 28-year-old right-hander off waivers from the Padres on Nov. 6 and just served up a homer to former top prospect Eloy Jimenez on an 0-2 pitch last weekend.
He has had a taste of the big leagues, but to disastrous results — a 17.28 ERA (32 ERs in 16.2 innings), 2.94 WHIP and 7 homers allowed in 14 games.
But Mazzoni is a former 2nd-round pick (2011 by the Mets out of North Carolina State) and has had some success in the minor leagues over the last three seasons — 107 Ks, 2.11 ERA, 1.00 WHIP in 72.2 innings while recovering from a shoulder injury.
While his track record doesn't inspire much confidence, Mazzoni could be a nice case study for the Cubs as they've completely revamped their organization-wide pitching infrastructure this winter and hope to change how they develop pitching.
7. Anthony Bass, RHP
No pitcher in the Cubs organization may have a better chance at becoming the next Anthony Swarzak than a guy who shares the same first name.
Bass, 30, is a non-roster invitee to spring training and comes with plenty of MLB experience under his belt (131 games, 18 starts) to unspectacular results (4.60 ERA, 1.41 WHIP, 6.0 K/9).
Before breaking out at age 31 in 2017, Swarzak had a 4.52 ERA, 1.38 WHIP and 5.8 K/9 in 217 big-league outings (32 starts).
Bass would need to find better results with his 93 mph fastball in 2018 and put it all together like Swarzak, but stranger things have happened.
8. Danny Hultzen, LHP
The former No. 2 overall pick (2011) has yet to reach the majors and hasn't pitched in Triple-A since 2013 in a career marred by injury.
Hultzen is still only 28 and while he hasn't pitched in over a year, he's working his way back from injury. It was a low-risk for the Cubs and one that could pay off if Hultzen actually stays healthy.
The southpaw has a career 2.86 ERA, 1.24 WHIP and 9.9 K/9 in 169.2 minor-league innings spread out across four seasons. He's always had the stuff capable of pitching in the big leagues, so with a little luck in the health department, maybe he can actually reach The Show and find a role in the Cubs bullpen.
Bonus: Jake Stinnett, RHP
The Cubs' former 2014 2nd-round pick, Stinnett is now 25 and has steadily risen through the Cubs system. He moved to the bullpen in 2017 and had stellar results (1.19 ERA, 1.02 WHIP, 10.7 K/9 in 14 games) while reaching Double-A Tennessee.
If Stinnett stays healthy, he could wind up as the second pitcher drafted by Epstein's front office to reach the big leagues.