Rowan Wick (1 option year remaining)
There isn't much to say about this duo. Rowan Wick was one of the more pleasant surprises for the Cubs in 2019. The Craig Kimbrel signing, and his struggles upon arrival, were a surprise of a different nature. There is no doubt both figure to play key roles in the Cubs bullpen plans next season. Despite the vast difference in experience and accomplishment, both rely on similar mid-to-upper-90s fastball and spike curveball as their primary weapons.
Hopefully, Kimbrel is able to get his fastball velocity back up at the higher end of the spectrum with a normal offseason, but the pitch has been trending down over the past couple years, so Kimbrel may need to adjust his approach to succeed if this is his new normal.
The Cubs badly need Wick to repeat his 2019 breakout.
Alec Mills, Duane Underwood, Jr.
Assuming he isn't traded this offseason, Tyler Chatwood will have a role with the Cubs as either a starter or reliever in 2020. It seems reasonable to project him to return to the same swingman role he occupied in 2019, but the development of Alec Mills opens the door to a full-time return to the rotation or into a higher leverage role in the pen next year.
Mills has always had a good changeup, but with his fringy fastball it was never enough on its own to keep hitters honest. He needed a more reliable breaking ball, and over the last two years Mills has turned both his slider and slow curve into viable weapons. The fastball still scares me if he is asked to take regular turns in the rotation, but he's shown me enough where I consider him a solid option to fill the swing role in the pen heading into 2020.
Like Mills, Duane Underwood, Jr. is out of options and in a make or break situation heading into next spring. While the Cubs should close the book for good on his life as a starter, he is capable of working as a short or long man out of the pen. He also relies heavily on an above average changeup. Unfortunately, despite being able to run his fastball up around 97, it lacks life, and when Underwood struggles to command he ends up getting knocked around. The ability is certainly there but it is likely Underwood enters 2020 on the outside looking in, and will either need to take a further step forward with his consistency, or he will need to take advantage of opportunities provided by the struggles or injuries of others.
40-Man Roster Depth
Adbert Alzolay (1 option year remaining), Colin Rea (2 option years remaining)
Even if Tyler Chatwood ends up in the rotation and Alec Mills fails to come through as the swingman, the Cubs have other arms with the potential to fill the role. The big name is Adbert Alzolay. But the organization also promoted former Padres 5th starter Colin Rea to the 40-Man Roster after he posted a bounceback campaign with Iowa, earning the award for the PCL Pitcher of the Year. Alzolay has the upside and Rea the experience. Both figure to get stretched out in Spring Training and could certainly end up as the top two starters in the Iowa rotation, but depending on how things play out with Chatwood and Mills there could be an Opening Day roster opportunity for one of them.
Entering his final option year, the Cubs really need to figure out the best long-term role for Alzolay. With two starting pitchers entering their contract year (Chatwood and Jose Quintana), if the Cubs do not feel confident projecting Alzolay as a replacement for one of them in 2021, then they need to strongly consider transitioning him to a full-time relief role during the year. It would do Alzolay a disservice to leave him in the Iowa rotation as long as the organization did with Underwood in 2019.
Dillon Maples (1 option year remaining), James Norwood (1 option year remaining)
The 2019 Iowa bullpen was as talented as any group I can remember the Cubs sending to AAA to begin a season. It only took about a week into the season before Kyle Ryan was summoned to Chicago, where he pitched well enough that the thought of returning him to Des Moines probably never crossed anyone's mind. Once Rowan Wick gained confidence with his new spike curveball grip he began making the most of his MLB opportunities, even if the Cubs were too slow to trust him. Wick was good from day one and only got better as the season progressed.
The rest of the Iowa group battled through inconsistencies though. Alzolay missed time due to injury. Underwood got stuck filling in as an injury replacement in the rotation for much of the first half. With the Chicago bullpen hemorrhaging leads, the Cubs would have benefited greatly if either of their two most talented bullpen arms (Dillon Maples, James Norwood) managed to make a breakthrough.
Alas, Maples continued his career-long battle to find the strikezone, and it wasn't until the second half when James Norwood upped his secondary pitch usage that his season took on new life. Norwood gained enough confidence in his slider to use it earlier in the count. Batters chased the pitch more often and made less contact when they did. By that time though, Wick had supplanted Norwood (and Maples) in the pecking order on the Iowa shuttle, so MLB opportunities were limited.
Norwood did finish the year with some impressive games with the big club in September so his arrow is pointing up heading into 2020. If either one of these two can stay locked in they have the talent to force their way into a MLB role. They are the exact type of power arms the team needs. The Cubs may not be able to count on either securing a full-time job next spring given their lack of consistency, but it would behoove the team to makes sure the roster has the flexibility to make room if they prove ready.
Tyson Miller, Matt Swarmer
These two figure to form part of the backbone of the Iowa rotation. Both are Rule 5 eligible, and there has to be serious consideration to promoting Miller to the 40-Man roster given his success with Tennessee during the first half of 2019. He found the goings in Iowa a bit more difficult to navigate, particularly since the AAA rabbit ball took a bite out of him with regularity, but Miller was starting to settle in during the final month of the season. He's heavily reliant on his fastball, which possessing some natural, late cutter action. Miller did make some strides with his breaking pitches but despite starter's size and stamina, Miller currently projects better as a MLB reliever, at least until he shows greater consistency with his secondaries.
Swarmer also struggled mightily keeping the ball in the park (36 HR allowed). But he proved to be a reliable innings eater (organizational high 151.1 IP) in the Iowa rotation. He throws plenty of strikes and possesses the size and stamina of a starter, but his over-the-top delivery has always led to issues against left-handed batters. They hit .324 against him in 2019. While many ingredients are there for him to project as a back-of-the-rotation starter that one hole in his game figures to push him to the pen eventually.
Dakota Mekkes, Michael Rucker, Craig Brooks, Oscar de la Cruz, Scott Effross, Corey Black
I'm a big believer in Dakota Mekkes as an MLB reliever. I've made no secret of that the past couple of seasons. His stuff doesn't measure up to Maples or Norwood, but he is capable of hitting the mid-90s, while his slider and change flash as average pitches. What separates Mekkes is his unique delivery. Not only does he employ a low 3/4 arm slot and slingy arm action, the 6'7" righty also pushes hard off the mound to close the distance to the hitter before releasing the ball. It is a combo of deception and extension which regularly eats up opposing hitters.
I was wrong in thinking Mekkes would force his way into a MLB job by the end of 2019, but I haven't lost faith he can do so in 2020. Lefties killed him in 2019, but had never been an issue for him in the past, including his previous 1/2 season with Iowa in 2018. He still needs to refine his control to limit free passes, but I do believe the Cubs would be wise to add him to the 40-Man prior to the Rule 5 draft. There are plenty of power arms hanging around the upper levels of the Minors with more pure talent but the package Mekkes offers is rare.
Another arm to keep an eye on is Michael Rucker. He made the transition to full-time reliever last year and while there were a few bumps in the road, he grew more comfortable as the year went along. His velocity began to tick up into the mid-90s more consistently and in combination with his solid breaking pitches don't be surprised if he puts together a strong 2020 season. Rucker is Rule 5 eligible and I'm not sure the Cubs have room to protect him. I'm very curious how many of the Miller/Mekkes/Rucker trio the Cubs choose to add to the 40-Man roster.
The remaining four pitchers on the list are a collection of guys at a crossroad. Their career's have stalled at the AA due to inconsistency (Craig Brooks, Scott Effross), injury (Corey Black), or both (Oscar de la Cruz). It is unlikely there will be room in Iowa for all of them so the competition for any jobs should be fierce.
Craig Brooks has a wipeout slider. He's used it to dominate AA, but his spotty control and straight fastball have yet to translate at the AAA level. He needs to develop some other weapon or improved command to fall back on.
Scott Effross hit a similar wall the past two years, but at the AA, rather than AAA level. We've already seen a midseason adjustment (to a side arm delivery) in the hopes Effross can unlock a new level of production. He pitched well in the AFL this fall which should give him some momentum heading into next season.
I honestly don't know what to make of Oscar de la Cruz at this point. He just hasn't been able to establish any consistency. The Cubs thought enough of him to add him to the 40-Man two years ago, but it is telling he went unclaimed on waivers late last season when the Cubs dropped him from the roster. But the Cubs still felt there is enough ability to re-sign him to a successor contract for 2020. His stuff and command plateaued a few years ago as the injuries mounted. He's been moved to relief and de la Cruz is in need of an extended stretch of health and on-field success.
Acquired way back in 2013 in exchange for Alfonso Soriano, two Tommy John surgeries limited Corey Black to just 7.1 innings over the past three seasons (all in 2018). When healthy, Black has flashed MLB quality stuff, including a mid-90s heat and a starter's mix of secondaries.