Aaron Bummer
25-Year-Old PitcherRP
2019 Fantasy Outlook
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. Read Past Outlooks
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Pitches in setup role
PChicago White Sox
May 14, 2019
Bummer worked around a walk in one-third of an inning to record his second hold in Monday's 5-2 win over the Indians.
Bummer was used as the bridge from starter Reynaldo Lopez to closer Alex Colome, a nod to the good work he's done since being called up from Triple-A Charlotte. He's allowed two hits and two walks over 9.1 scoreless innings since his promotion and appears to be in the mix for high-leverage and setup work. The eighth inning had been the domain of Kelvin Herrera, but he's allowed runs in six of his last 10 appearances, a stretch that includes 14 hits, six walks and 10 runs allowed.
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Pitching Stats
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Left/Right Pitching Splits
Since 2017
BAA Batters K BB H 2B 3B HR
Since 2017vs Left .200 121 28 9 22 4 0 2
Since 2017vs Right .262 152 34 19 34 3 1 3
2019vs Left .125 16 5 0 2 0 0 0
2019vs Right .056 22 5 3 1 0 0 0
2018vs Left .245 57 15 3 13 3 0 0
2018vs Right .338 87 20 7 27 2 1 1
2017vs Left .171 48 8 6 7 1 0 2
2017vs Right .188 43 9 9 6 1 0 2
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Home/Away Pitching Splits
Since 2017
ERA at Home
No Stats
ERA at Home
ERA at Home
Since 2017Home 2.25 0.98 40.0 1 3 0 9.2 2.5 0.7
Since 2017Away 6.00 1.88 24.0 0 1 0 7.9 6.4 0.8
2019Home 0.00 0.79 6.1 0 0 0 9.9 4.3 0.0
2019Away 0.00 0.25 4.0 0 0 0 6.8 0.0 0.0
2018Home 2.66 0.98 20.1 0 1 0 10.2 0.9 0.4
2018Away 7.15 2.65 11.1 0 0 0 9.5 6.4 0.0
2017Home 2.70 1.05 13.1 1 2 0 7.4 4.1 1.4
2017Away 7.27 1.62 8.2 0 1 0 6.2 9.3 2.1
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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 this season's data (min 20 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.
    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.
94.8 mph
Left On Base
Exit Velocity
83.5 mph
Spin Rate
2006 rpm
Balls Hit 95+ MPH
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Stats Vs Today's Lineup
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Recent RotoWire Articles Featuring Aaron Bummer
Mound Musings: Checking the NL Bullpens
5 days ago
Brad Johnson looks at National League closer situations, where in San Francisco closer Will Smith is doing so well, he may be a target in trade talks later this season.
AL FAAB Factor: Waiver Pickups of the Week
August 20, 2017
Erik Siegrist wades into the free-agent pool in the American League and thinks Willy Adames is more than ready to make his big-league debut for the Rays.
2018 Fantasy Outlook
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
No earned runs allowed
PChicago White Sox
May 12, 2019
Bummer struck out one in a perfect inning in Sunday's 5-1 win over the Blue Jays.
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Joins big-league club
PChicago White Sox
April 28, 2019
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Optioned to Triple-A
PChicago White Sox
March 18, 2019
Bummer was optioned to Triple-A Charlotte on Monday.
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Joins big-league club
PChicago White Sox
September 1, 2018
Bummer was recalled from Triple-A Charlotte on Saturday.
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Sent to minors
PChicago White Sox
June 6, 2018
Bummer was optioned to Triple-A Charlotte on Wednesday, Daryl Van Schouwen of the Chicago Sun-Times reports.
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