Zack Kelly

Zack Kelly

30-Year-Old PitcherRP
Boston Red Sox AAA
2025 Fantasy Outlook
There was no outlook written for Zack Kelly in 2025. Check out the latest news below for more on his current fantasy value.
$Signed a one-year contract with the Red Sox in March of 2025.
Sent to Triple-A
PBoston Red Sox  AAA
May 27, 2025
Kelly was optioned to Triple-A Worcester on Tuesday.
ANALYSIS
Kelly got the call Sunday and gave up two runs (one earned) on one hit and one walk with zero strikeouts in two innings against the Orioles. Richard Fitts (pectoral) was activated in a corresponding move.
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Pitching Stats
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2025
2024
2023
2022
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2024 MLB Game Log
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2023 MLB Game Log
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Pitching Appearances Breakdown
Average Pitch Count
24
Last 10 Games
24
Last 5 Games
28
How many pitches does Zack Kelly 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 Zack Kelly 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 2023
 
 
-14%
BAA vs RHP
2025
 
 
-26%
BAA vs LHP
2024
 
 
-25%
BAA vs RHP
2023
 
 
-4%
BAA vs RHP
BAA Batters K BB H 2B 3B HR
Since 2023vs Left .237 156 34 23 31 9 0 7
Since 2023vs Right .205 181 44 15 33 8 0 4
2025vs Left .227 25 4 2 5 3 0 0
2025vs Right .308 28 7 1 8 1 0 1
2024vs Left .242 107 26 15 22 3 0 7
2024vs Right .182 134 35 12 22 5 0 3
2023vs Left .222 24 4 6 4 3 0 0
2023vs Right .214 19 2 2 3 2 0 0
Home/Away Pitching Splits
Since 2023
 
 
-12%
ERA on Road
2025
 
 
-64%
ERA on Road
2024
 
 
-14%
ERA on Road
2023
 
 
-78%
ERA at Home
ERA WHIP IP W L SV K/9 BB/9 HR/9
Since 2023Home 4.89 1.51 42.1 2 4 0 8.7 4.9 1.1
Since 2023Away 4.29 1.07 35.2 5 0 0 9.3 3.8 1.5
2025Home 13.50 2.14 4.2 0 1 0 5.8 3.9 0.0
2025Away 4.91 0.82 7.1 1 0 0 9.8 1.2 1.2
2024Home 4.22 1.44 32.0 2 3 0 9.6 4.8 1.4
2024Away 3.65 1.01 24.2 4 0 0 9.9 3.6 1.8
2023Home 1.59 1.41 5.2 0 0 0 6.4 6.4 0.0
2023Away 7.36 1.91 3.2 0 0 0 4.9 9.8 0.0
Minor League Left/Right Pitching Splits (AAA)
Since 2023
 
 
-56%
BAA vs RHP
2025
 
 
-36%
BAA vs RHP
2024
 
 
-100%
BAA vs RHP
2023
 
 
-75%
BAA vs RHP
BAA Batters K BB H 2B 3B HR
Since 2023vs Left .209 53 14 10 9 3 0 3
Since 2023vs Right .093 57 17 13 4 0 1 1
2025vs Left .273 26 7 4 6 2 0 2
2025vs Right .176 28 8 10 3 0 1 0
2024vs Left .056 24 7 6 1 1 0 0
2024vs Right .000 22 6 2 0 0 0 0
2023vs Left .667 3 0 0 2 0 0 1
2023vs Right .167 7 3 1 1 0 0 1
Stat Review
How does Zack Kelly 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
3.67
 
K/9
8.3
 
BB/9
2.3
 
HR/9
0.8
 
Fastball
95.8 mph
 
ERA
8.25
 
WHIP
1.33
 
BABIP
.344
 
GB/FB
1.45
 
Left On Base
27.4%
 
Exit Velocity
79.7 mph
 
Barrels/BBE
4.3%
 
Spin Rate
2333 rpm
 
Balls Hit 95+ MPH
23.2%
 
Swinging Strike
9.5%
 
Advanced Pitching Stats
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Defensive Stats
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Stats Vs Today's Lineup
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2023 Fantasy Outlook
Kelly was a journeyman reliever earlier in his minor-league career. He gained fastball velocity during the off year in 2020 and came back racking up the strikeouts in 2021 and 2022, culminating with him fanning 72 batters (34.4 percent) in 49.2 innings at Triple-A Worcester before earning his MLB debut last season. In addition to his mid-90s fastball, Kelly sports a plus changeup that has similar movement characteristics to Devin Williams' famous "airbender" changeup. Kelly probably won't get saves as a rookie, but he could offer value in leagues where relievers who post good ratios and strikeouts are useful.
More Fantasy News
Gets call from Triple-A
PBoston Red Sox  AAA
May 25, 2025
The Red Sox recalled Kelly from Triple-A Worcester on Sunday, Jen McCaffrey of The Athletic reports.
ANALYSIS
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Moves back to Triple-A
PBoston Red Sox  AAA
April 22, 2025
The Red Sox optioned Kelly to Triple-A Worcester on Tuesday.
ANALYSIS
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Set to be optioned to Triple-A
PBoston Red Sox  AAA
April 22, 2025
The Red Sox will option Kelly to Triple-A Worcester prior to Tuesday's game against the Mariners, Chris Cotillo of MassLive.com reports.
ANALYSIS
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Secures bullpen spot
PBoston Red Sox  AAA
March 25, 2025
Manager Alex Cora announced Tuesday that Kelly has made the Opening Day roster, Ian Browne of MLB.com reports.
ANALYSIS
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Sent to minors
PBoston Red Sox  AAA
September 14, 2024
The Red Sox optioned Kelly to Triple-A Worcester on Saturday, Julian McWilliams of The Boston Globe reports.
ANALYSIS
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Latest Fantasy Rumors
Should soon return to majors
PBoston Red Sox  AAA
May 28, 2024
Chris Cotillo of The Springfield Republican expects Kelly's stay at Triple-A Worcester to be a short one after being optioned Sunday.
ANALYSIS
The right-hander has a 2.16 ERA and 1.26 WHIP across 16.2 innings for Boston this season, so it's only a matter of time before he's back in the big-league bullpen. Kelly likely won't be in the high-leverage mix for the Red Sox anytime soon, but it's not completely out of the question if the club trades away the likes of Kenley Jansen and Chris Martin, both of whom are pending free agents, this summer.
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