A 2020 Cubs Bullpen Primer
The bullpen was a weak point for the Cubs in 2019. What will it look like in 2020?
Ben Bailey · December 22, 2019 · 12m ·

The bullpen was an area of concern in 2019, enough so that the Cubs signed Craig Kimbrel mid-season. While the Cubs haven't made any major acquisitions this offseason, they have added several pitchers on minor-league deals. I thought it would be interesting and useful to look at each of the in-house candidates the Cubs have who could end up in the bullpen in 2020.

As it stands now, the Cubs have lost three important relievers from 2019:

The Cubs have a couple different groups of pitchers who they hope will fill the gaps left by the departures above.

The core

These pitchers are virtually guaranteed to be in the bullpen all year, and will hopefully form a solid core.

Craig Kimbrel

The Cubs’ closer had a rough 2019. Kimbrel pitched just 20.2 innings, but he was the least valuable Cub, worth -1.0 fWAR. Mike Montgomery pitched poorly for the Cubs in 2019, but Kimbrel was twice as bad in 6.1 fewer innings. His 6.53 ERA was rough, but his FIP was even worse at 8.00. Luckily, Kimbrel's lack of success was due in large part to his impossibly high 36.0% home run per flyball rate (his previous career high was 13.6% in 2015), which should regress in 2020.

The most concerning thing with Kimbrel is that his velocity peaked in 2017: 98.3 MPH on his four-seamer, and 87.3 MPH on his curveball. Those numbers were down to 96.2 and 85.9 MPH on average, respectively, and they fluctuated a fair amount between outings. Kimbrel still had the same strikeout percentage as Yu Darvish, which is quite good, but he had a higher walk rate than Tyler Chatwood, and while his strikeout rate was high for a Cub, it was the lowest of any season of his career. The Steamer projection system projects him to be the 36th-best pitcher in baseball next season by FIP, which isn't bad, but the projection of 3.58 would be the worst of his career. Still, that would make him more valuable by WAR than any Cubs reliever in 2019, so I'm guessing the team would take it. It seems he's not the lock-down closer he once was, though, so the team needs to fill out the bullpen behind him.

Rowan Wick

Wick may have been one of the best parts of the Cubs’ season. He ended up pitching 33.1 innings for the Cubs, with a 2.43 ERA and a 2.82 FIP. Wick probably won't be as good as that again in 2020, considering he didn't give up a single home run. While the underlying numbers don't quite match up with Wick's stellar 2019 performance, he did post the 30th-highest groundball rate in the majors among relievers who pitched at least 30 innings. Even if Wick regresses, he should still be a very useful reliever for the Cubs.

Kyle Ryan

Ryan was a pleasant surprise as a groundball machine. He had the 13th-highest ground ball rate among qualified relievers, and while he didn't miss bats or even necessarily limit hard contact, he limited hard contact in the air, ranking in the 88th percentile of expected slugging percentage. Ryan was notably better against lefties: he allowed just a .571 OPS against lefties, but .736 OPS against righties. He's good enough to still be quite useful despite the new three-batter-minimum rule coming into effect in 2020, but one thing to watch is that he gave up five homers all year, and all were to righties. In his last three outings of the season against the Cardinals, he gave up six runs, walking four and striking out just two. Excluding those final three appearances, his ERA decreases from 3.54 to 2.79, and his OPS allowed decreases from .669 to .619. Obviously, you can't just throw out those appearances, but I'm not too worried about Ryan going forward–he'll be a valuable member of the bullpen in 2020 and beyond.

Familiar faces

These are pitchers we saw with the Cubs in 2019 who are poised to potentially play a bigger role in 2020.

Brad Wieck

As much as I loved Carl Edwards Jr., it's looking like trading him to the Padres could end up paying dividends for the Cubs. Edwards was released and signed with the Mariners, while Wieck made some tweaks to his curveball. With the Cubs in 2019, he faced 38 batters and gave up just two hits and four walks while striking out 18. That's a 36.8% K-BB rate, which would have been behind only Josh Hader among qualified relievers. You certainly can't expect Wieck to keep up those numbers over a full season, but it's a promising sign. His curve spin rate increased by 233 RPM after he was traded to the Cubs. Wieck also provides a nice contrast to the Cubs’ other established lefty, Kyle Ryan, in that Wieck's delivery is over the top and he throws harder than average, while Ryan has one of the left-most release points in baseball and tops out in the low 90s.

Duane Underwood Jr.

Underwood finished his major league season with an ugly line: 11.2 IP, a 5.40 ERA, and a 4.24 FIP. However, he also struck out 13 batters while walking only three. He had an amazing debut, striking out six consecutive batters over two innings, and while he didn't live up to that potential the rest of the season, during that appearance it was easy to picture Underwood being useful out of the bullpen. Underwood is out of minor league options, so this could be his last chance with the team.

Dillon Maples

Ah, Dillon Maples. I've given up hope that he'll be an effective major league reliever with the Cubs, and it seems as if the Cubs may have as well. Maples threw three different pitches in the majors this season: his four-seamer ranked first in average spin (minim um 100 pitches), his slider was fifth, and his curveball was fourth. However, his active spin percentage on his fastball was just 52.4%, and his slider was just 58.0%. He doesn't get substantial movement on his fastball, but his slider is another story, and it seems particularly tough on righties, as I catalogued here.

Maples faced 54 batters in the majors this year and only gave up six hits and struck out 18 batters. He also walked 10. Over a full season, Maples’ 33.3% strikeout rate would have tied him for 21st among qualified relievers, which is quite good. However, his 18.5% walk rate would have been the highest among qualified relievers. It is very difficult for a reliever with a walk rate that high to be good, though not impossible.

Maples has faced 110 batters with the Cubs, with a line of 19 hits, 20 runs, 4 home runs, 21 walks, 6 HBP, and 38 strikeouts. He probably wouldn't be the worst reliever on the Cubs, but it's hard to imagine Maples being a cornerstone of the bullpen.

Danny Hultzen

A great story and not a bad pitcher, Hultzen is on a minor league deal and will probably be up with the Cubs at some point, provided he stays healthy. Considering no team offered him a major league contract, however, my expectations remain low.

James Norwood

Norwood has a lively arm, but hasn't shown much in his time in the majors. He's a good bullpen depth piece that could develop into more, but seems limited to seventh-inning upside.

Low-risk additions

The Cubs have brought all of these pitchers into the organization at a low cost. They're either coming off of years in which they were bad or injured, or they haven't proven themselves in the majors. Still, if just one of these pitchers is a league-average reliever for the Cubs in 2020, it will be considered a success.

Dan Winkler

Winkler had 93rd-percentile spin on his four-seam fastball in 2019, but he pitched poorly enough to be released by the Braves. In 2018, though, he put up a 3.43 ERA and a 2.76 FIP in 60.1 innings. At such a low cost, the Cubs will be happy even if he split the difference between his previous two seasons–his average FIP of 4.30 would have been better than both Steve Cishek and Pedro Strop in 2019.

Ryan Tepera

Tepera pitched poorly in 21.2 innings with the Blue Jays last year, but he was pretty good in 2017 (3.59 ERA/3.75 FIP) and durable (77.2 innings). He was worse in 2018 in all three of those categories, and then spent much of 2019 injured. The Cubs took a flyer on him and will hope he can regain his 2017 form.

Trevor Megill

Megill was a Rule-5 draft pick from the Padres, which means he needs to stay on the active roster or the fifteen-day IL for the whole season, lest he be offered back to the Padres. He pitched well in both AA and AAA in 2019, striking out 71 batters in 50.1 AAA innings. The ZiPS projection system projects Megill to be an above-average reliever, and according to FanGraphs, Megill can touch 96 with his fastball while his 6'8” height provides a difficult arm-angle. The main problem with Megill is that if he struggles he can't be demoted to AAA without risking losing him.

Jharel Cotton

Cotton spent all of 2018 and part of 2019 rehabbing from Tommy John surgery, and when he pitched in the minors in 2019, he was bad. However, he was acquired at a low cost and used to be a fairly well-regarded sleeper pick as a prospect. Cotton could start in a pinch, but I'm guessing the Cubs picked him up to see what he could do in relief with his devastating changeup.

CD Pelham

Pelham is a tall 6'6” lefty who sits in the mid 90s with his fastball and touches 99. However, his command is rough. In 2019, Pelham walked three more batters than he struck out across AA and AAA with the Rangers. Pelham has obvious upside with low-risk, but I wouldn't count on him making an impact with the Cubs this season.

Starters/Long-Relief

This group of pitchers could either fit into the fifth spot in the rotation or in long relief.

Tyler Chatwood

Chatwood was surprisingly good last year, and useful in a variety of roles. I wrote about Chatwood a couple times in 2019, and I think he will continue to be a valuable pitcher for the Cubs, whether in relief or as a starter. As it stands now, he seems to be the favorite for the fifth-starter role, and I'm curious to see how his success from last season will translate.

Alec Mills

Mills is very intriguing to me. He fits in great as a back-of-the-rotation starter, or as a long-man. Mills is fun to watch, as he pairs plus command with a slow curve–his average curveball was the slowest (67.6 MPH) among any pitcher who threw at least 250 pitches last year. It's hard to imagine Mills ever being dominant, but I believe he'll be a valuable major league pitcher in 2020. The only issue is that he's out of minor league options, meaning the Cubs can't send him to the minors without first placing him on waivers. I expect that Mills or Chatwood will get the fifth rotation spot, and the other will be the long man in the bullpen.

Adbert Alzolay

Alzolay had a fantastic debut with the Cubs in 2019, but his overall season line was not great (7.30 ERA, 7.75 FIP in 12.1 innings). Following his last start (an ugly 2.2IP 10H 7R 1BB 3K line), he was demoted back to AAA and then got injured. Alzolay made one unremarkable relief appearance in September with the major league team to finish his year. He has a pretty good fastball and a great curveball, but a mercurial changeup, which would lead me to expect he'll be tried out as a reliever in 2020. This next season will be Alzolay's last option year, so the Cubs need to figure out how he'll fit into their roster going forward. Alzolay could still be a starter, but the lack of a consistent third pitch, injury concerns, and unspectacular command suggest a relief role in his future. Still, he could excel there.

Colin Rea

Rea is 29 years old, and the Cubs felt confident enough in his future that they added him to their 40-man roster in November. Judging by his minor-league numbers, it doesn't seem likely that Rea will be a great starter or reliever in 2020, but he is a good depth piece, and it would be nice to see him make it back to the majors after being injured in his previous start.


With the team under a mandate to move money and get cheaper, it seems like some combination of these players will constitute the Cubs’ bullpen in 2020. In fact, it's very possible that we'll see all 17 of these pitchers with the Cubs next season. While it doesn't look like a dominant unit like the Yankees or the Rays, there's enough upside that I'm intrigued to see what the bullpen provides.


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