Aaron Bummer
27-Year-Old PitcherRP
2021 Fantasy Outlook
The closer job for the White Sox briefly opened up after Alex Colome left in free agency, but despite his recent success Bummer was denied a chance to compete for it when the club signed Liam Hendriks. It's tough to get too excited about the 27-year-old lefty's 2020 campaign, as bicep issues limited him to just nine appearances, but Bummer was excellent when available, posting a 0.96 ERA and a 36.8 K%. It's difficult to expect anything close to a repeat of that performance in 2021 given the size of the sample and the fact that he posted a rather modest 22.9 K% during his breakout 2019 campaign. Still, that's now two years where he's looked like a high-leverage option, with an elite 71.7% groundball rate over that stretch keeping him in that tier despite modest numbers elsewhere. He doesn't have a traditional closer's profile, but Bummer should remain in the late-inning mix. Read Past Outlooks
RANKSFrom Preseason
#525
ADP
$Signed a five-year, $16 million contract extension with the White Sox in February of 2020.
Fighting mechanics
PChicago White Sox
May 2, 2021
Bummer struck out two over a scoreless inning in Saturday's 7-3 win over Cleveland.
ANALYSIS
The White Sox's bullpen, projected as a strength entering the season, posted a 4.50 ERA and blew seven saves during April. Bummer has not been excluded from the struggles. He told Jared Wyllys of the Chicago Sun-Times that a dropoff in his performance this season is due to a mechanical issue. Bummer's strikeouts are down and walks up thus far in 2021, but he still has a respectable 2.08 ERA over 8.2 innings.
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Pitching Stats
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2021
2020
2019
2018
2017
2021 MLB Game Log
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2020 MLB Game Log
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2019 MLB Game Log
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2018 MLB Game Log
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2017 MLB Game Log
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Pitching Appearances Breakdown
Average Pitch Count
16
Last 10 Games
15
Last 5 Games
16
How many pitches does Aaron Bummer generally throw?
 
1-10
 
11-20
 
21-30
 
31-40
 
41-50
 
51-60
 
61-70
 
71-80
 
81-90
 
91-100
 
101-110
 
111-120
 
121+
 
1-10
 
11-20
 
21-30
 
31-40
 
41-50
 
51-60
 
61-70
 
71-80
 
81-90
 
91-100
 
101-110
 
111-120
 
121+
 
1-10
 
11-20
 
21-30
 
31-40
 
41-50
 
51-60
 
61-70
 
71-80
 
81-90
 
91-100
 
101-110
 
111-120
 
121+
What part of the game does Aaron Bummer generally pitch?
 
 
 
1st
 
 
 
2nd
 
 
 
3rd
 
 
 
4th
 
 
 
5th
 
 
 
6th
 
 
 
7th
 
 
 
8th
 
 
 
9th
 
Extra
 
 
 
1st
 
 
 
2nd
 
 
 
3rd
 
 
 
4th
 
 
 
5th
 
 
 
6th
 
 
 
7th
 
 
 
8th
 
 
 
9th
 
Extra
 
 
 
1st
 
 
 
2nd
 
 
 
3rd
 
 
 
4th
 
 
 
5th
 
 
 
6th
 
 
 
7th
 
 
 
8th
 
 
 
9th
 
Extra
% Games Reaching Innings Threshold
% Games By Number of Innings Pitched
Left/Right Pitching Splits
Since 2019
 
 
-3%
BAA vs LHP
2021
 
 
-41%
BAA vs LHP
2020
 
 
-57%
BAA vs RHP
2019
 
 
-5%
BAA vs LHP
BAA Batters K BB H 2B 3B HR
Since 2019vs Left .185 124 32 5 22 2 0 1
Since 2019vs Right .191 218 53 30 35 2 0 3
2021vs Left .188 17 7 1 3 0 0 0
2021vs Right .316 25 4 5 6 0 0 0
2020vs Left .231 13 4 0 3 0 0 0
2020vs Right .100 25 10 5 2 0 0 0
2019vs Left .178 94 21 4 16 2 0 1
2019vs Right .188 168 39 20 27 2 0 3
More Splits View More Split Stats
Home/Away Pitching Splits
Since 2019
 
 
-11%
ERA at Home
2021
 
 
-14%
ERA on Road
2020
 
 
-100%
ERA on Road
2019
 
 
-27%
ERA at Home
ERA WHIP IP W L SV K/9 BB/9 HR/9
Since 2019Home 1.88 1.19 43.0 0 0 1 8.4 4.2 0.6
Since 2019Away 2.11 0.96 42.2 1 1 0 9.5 3.2 0.2
2021Home 2.25 1.75 4.0 0 0 0 11.3 4.5 0.0
2021Away 1.93 1.71 4.2 0 1 0 11.6 7.7 0.0
2020Home 2.25 2.00 4.0 0 0 0 9.0 11.3 0.0
2020Away 0.00 0.38 5.1 1 0 0 16.9 0.0 0.0
2019Home 1.80 1.03 35.0 0 0 1 8.0 3.3 0.8
2019Away 2.48 0.95 32.2 0 0 0 8.0 3.0 0.3
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Stat Review
How does Aaron Bummer compare to other relievers?
This section compares his stats with all relief pitcher seasons from the previous three seasons (minimum 30 innings)*. The bar represents the player's percentile rank. For example, if the bar is halfway across, then the player falls into the 50th percentile for that stat and it would be considered average.

* Exit Velocity, Barrels/BBE %, Balls Hit 95+ MPH %, and Spin Rate are benchmarked against 2019 data (min 30 IP). See here for more exit velocity/barrels stats plus an explanation of current limitations with that data set.
  • K/BB
    Strikeout to walk ratio.
  • K/9
    Average strikeouts per nine innings.
  • BB/9
    Average walks per nine innings.
  • HR/9
    Average home runs allowed per nine innings.
  • Fastball
    Average fastball velocity.
  • ERA
    Earned run average. The average earned runs allowed per nine innings.
  • WHIP
    Walks plus hits per inning pitched.
  • BABIP
    Batting average on balls in play. Measures how many balls in play against a pitcher go for hits.
  • GB/FB
    Groundball to flyball ratio. The higher the number, the more likely a pitcher is to induce groundballs.
  • Left On Base
    The percentage of base runners that a pitcher strands on base over the course of a season.
  • Exit Velocity
    The speed of the baseball as it comes off the bat, immediately after a batter makes contact.
  • Barrels/BBE
    The percentage of batted ball events resulting in a Barrel. A Barrel is a batted ball with similar exit velocity and launch angle to past ones that led to a minimum .500 batting average and 1.500 slugging percentage.
  • Spin Rate
    Spin Rate is the rate of spin on a baseball after it is released. It is measured in revolutions per minute (rpm).
  • Balls Hit 95+ MPH
    The percentage of batted balls hit that met or exceeded the 95 MPH threshold.
  • Swinging Strike
    The percentage of pitches that result in a swing and a miss.
K/BB
1.83
 
K/9
11.4
 
BB/9
6.2
 
HR/9
0.0
 
Fastball
96.1 mph
 
ERA
2.08
 
WHIP
1.73
 
BABIP
.401
 
GB/FB
9.50
 
Left On Base
73.3%
 
Exit Velocity
83.6 mph
 
Barrels/BBE
2.1%
 
Spin Rate
2047 rpm
 
Balls Hit 95+ MPH
29.2%
 
Swinging Strike
11.0%
 
Advanced Pitching Stats
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Defensive Stats
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Stats Vs Today's Lineup
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Past Fantasy Outlooks
2020
2019
2018
Bummer spent the previous two seasons as an unremarkable middle reliever for the White Sox, but he turned into a high-leverage option in his age-26 season and recorded 27 holds. Overall he had a 2.13 ERA and 0.99 WHIP across 67.2 innings, and he held both righties and lefties to a sub-.200 average. The left-hander interestingly saw his strikeout rate drop (22.9%) and his walk rate rise (9.2%), but he relied much more heavily on his fastball (76.4% usage) and saw an uptick in velocity (95.5 mph) to help induce a 72.1% groundball rate. Barring any free-agent additions, Bummer should enter spring training in the setup role to closer Alex Colome, who went 30-for-33 in save opportunities.
After vaulting up the organizational ladder in 2017, Bummer was rewarded with an Opening Day roster spot. Early on, the southpaw was used almost exclusively in one- or two-batter stints, largely as a specialist. The results were promising, as he posted a 3.26 ERA and a 21:6 K:BB in 19.1 frames before being shuttled back to the minors. He returned to the big leagues for the month of September and was touched up a bit to the tune of eight runs in 12.1 innings. Despite the struggles at the end, 2018 was largely a success for the 25-year-old. His 65:21 K:BB in 61.2 innings between the majors and minors was strong, and he held left-handed hitters to a .245 batting average. Plus, his 2.44 FIP fell well below his 4.26 ERA for the season, suggesting he was the subject of some bad luck. He figures to have a role in the middle innings in 2019.
Last season marked the first complete campaign for Bummer since he underwent Tommy John surgery in 2015. The White Sox started him at High-A, and he pitched at four levels last season while eventually getting the call to Chicago. In the minors, he struck out a batter per inning at each of his three stops, but he struggled to miss bats as a big-league reliever in his debut. Additionally, his walk rate spiked to a career-worst 6.1 BB/9, which kept the White Sox from relying on him in high-leverage spots. There are a few positives, however, including a track record of better control and his ability to get outs on the ground (54.4 percent groundball rate). With a low-90s fastball and slider combo, Bummer should get more opportunities to stick with the White Sox in 2018, but he may wind up bouncing between Charlotte and Chicago if he fails to cut back on the free passes.
More Fantasy News
Tagged with Opening Day loss
PChicago White Sox
April 2, 2021
Bummer (0-1) allowed two unearned runs on two hits and one walk while striking out one over two-thirds of an inning to take the loss against the Angels on Thursday.
ANALYSIS
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Makes Cactus League debut
PChicago White Sox
March 12, 2021
Bummer allowed two runs on one hit and two walks while striking out two in two-thirds of an inning during Thursday's spring game against the Reds.
ANALYSIS
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Throws in 'B' game
PChicago White Sox
March 8, 2021
Bummer threw a perfect inning in a "B" game Sunday against the Dodgers, Scott Merkin of MLB.com reports.
ANALYSIS
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Arrives late to camp
PChicago White Sox
February 25, 2021
Bummer arrived late to spring training but is not behind other pitchers, Scott Merkin of MLB.com reports.
ANALYSIS
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Scoreless in return
PChicago White Sox
September 25, 2020
Bummer allowed a hit and struck out one over a scoreless eighth inning in Thursday's 5-4 loss to Cleveland.
ANALYSIS
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