P | Boston Red Sox
Bats/Throws: R/R | 6' 3" 231 lbs | Age: 30
W L ERA G GS SV IP SO WHIP
2023 0 0 3.86 8 0 0 9.1 6 1.61
2024 6 3 3.97 49 3 0 56.2 61 1.25
2025 1 3 4.58 28 0 0 35.1 35 1.33
4 Seasons 8 6 4.15 98 3 0 115 113 1.31
G W-L ERA IP SO WHIP
2023 8 0-0 3.86 9.1 6 1.61
2024 49 6-3 3.97 56.2 61 1.25
2025 28 1-3 4.58 35.1 35 1.33
4 Seasons 98 8-6 4.15 115 113 1.31
MLB Percentile Rankings
Movement Profile (Induced Break)
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Statcast Statistics

Season Age Pitches Batted
Balls
Barrels Barrel % Barrel/PA Exit
Velocity
Max EV Launch
Angle
LA Sweet-
Spot %
XBA XSLG WOBA XWOBA XWOBACON HardHit% K% BB% ERA xERA
2022 27 222 44 3 6.8 5.1 85.0 109.2 12.6 29.5 .197 .342 .316 .260 .286 25.0 18.6 6.8 3.95 2.76
2023 28 181 26 2 7.7 4.7 89.5 109.9 8.7 30.8 .225 .381 .357 .362 .315 46.2 14.0 18.6 3.86 5.74
2024 29 957 151 15 9.9 6.2 87.2 114.4 12.0 35.1 .226 .410 .300 .317 .381 31.1 25.3 11.2 3.97 4.22
2025 30 582 102 5 4.9 3.3 86.2 107.7 13.5 37.3 .236 .348 .318 .291 .336 31.4 23.0 7.9 4.58 3.51
Player 1942 323 25 7.7 5.1 86.8 114.4 12.3 34.7 .226 .380 .313 .306 .349 31.6 22.8 10.3
MLB 7.2 4.9 88.6 122.9 12.4 33.3 .245 .404 .315 .315 .368 37.0 22.2 8.4
! Note: All figures in this table cover the period 2015-present.

Statcast Pitch Arsenal

Kelly relies on 6 pitches.
Cutter
(31.3%) ,
Sweeper
(20.7%) ,
Four Seamer
(19.8%) ,
Sinker
(15.3%) ,
Changeup
(11.9%) ,
Curveball
(1.0%) ,


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Pitch Tracking



Batted Ball Profile

AIR: Fly Balls + Line Drives + Popups All Batted Balls Batted Ball Breakdown
Season GB % AIR % FB % LD % PU % Pull % Straight % Oppo % Pull GB % Straight GB % Oppo GB % Pull AIR % Straight AIR % Oppo AIR %
2022 45.5 54.5 31.8 13.6 9.1 36.4 40.9 22.7 15.9 20.5 9.1 20.5 20.5 13.6
2023 53.8 46.2 26.9 19.2 0.0 34.6 42.3 23.1 23.1 23.1 7.7 11.5 19.2 15.4
2024 47.7 52.3 24.5 20.5 7.3 38.4 39.7 21.9 25.2 17.2 5.3 13.2 22.5 16.6
2025 43.1 56.9 24.5 25.5 6.9 39.2 32.4 28.4 25.5 11.8 5.9 13.7 20.6 22.5
Player 46.4 53.6 25.7 21.1 6.8 38.1 37.8 24.1 23.8 16.4 6.2 14.2 21.4 18.0
MLB 44.2 55.8 24.0 24.7 7.1 37.4 37.4 25.1 20.6 17.6 5.9 16.7 19.7 19.3
! Note: All figures in this table cover the period 2015-present.

Quality of Contact

Season Weak % Topped % Under % Flare/Burner % Solid % Barrel % Barrel/PA
2022 9.1 31.8 31.8 13.6 4.5 6.8 5.1
2023 3.8 38.5 30.8 19.2 0.0 7.7 4.7
2024 6.0 36.4 21.2 21.9 4.6 9.9 6.2
2025 7.8 31.4 28.4 21.6 5.9 4.9 3.3
Player 6.8 34.4 25.7 20.4 4.6 7.7 5.1
MLB 4.0 32.4 24.9 24.4 5.9 7.2 4.9
! Note: All figures in this table cover the period 2015-present.

Pitch Movement


How this works: This section shows two different ways to evaluate pitch movement. On the left, “Total Movement” shows the real-world movement of a pitch, including the forces of gravity, which affects every pitch thrown. Since gravity requires time, and slower pitches aren't 'better' just because they have more time to move, a pitch's movement is compared to other pitches of the same pitch type, within +/- 2 MPH and +/- 0.5 feet of extension/release. On the right, Induced Movement (or IVB) is reported without gravity, and attempts to isolate movement created by the pitcher's ability to spin and manipulate the ball.
Total Movement (in inches, w/ gravity)Induced Movement (in inches, w/o gravity)
YearPitchTeamHand#MPHVertical
Drop
vs.
Comparable
Horizontal
Break
vs.
Comparable
Vertical
Break
vs. AvgHorizontal
Break
vs. Avg
2025 Sinker BOS R 89 96.1 18.4 -3.1 16.0ARM 0.7 11.4 -4.0 16.0ARM 0.9
2025 Changeup BOS R 69 83.1 38.4 1.9 18.0ARM 2.9 1.5 2.6 18.0ARM 3.6
2025 4-Seam Fastball BOS R 115 96.1 14.8 -1.0 9.5ARM 1.8 15.0 -0.8 9.5ARM 1.9
2025 Cutter BOS R 182 91.8 23.6 -0.2 2.3GLV 0.8 8.8 0.5 2.3GLV 0.1
2025 Curveball BOS R 6 82.3 47.5 -2.7 8.6GLV 0.7 -7.2 -2.7 8.6GLV -0.5
2025 Sweeper BOS R 120 81.8 38.5 -0.5 17.2GLV 3.1 2.7 -1.6 17.2GLV 3.3
2024 Cutter BOS R 209 91.1 26.2 -1.9 2.2GLV 0.2 6.8 -1.5 2.2GLV -0.5
2024 Changeup BOS R 200 83.6 38.9 3.8 18.0ARM 3.5 0.5 4.4 18.0ARM 3.8
2024 Sweeper BOS R 260 82.2 38.1 -0.3 17.6GLV 3.6 2.5 -1.0 17.6GLV 3.5
2024 4-Seam Fastball BOS R 286 96.5 14.6 -0.8 9.7ARM 1.8 14.9 -0.8 9.7ARM 2.1
! Note: Years are in reverse order.

Run Values by Pitch Type

Year Pitch Type Team RV/100 Run Value Pitches % PA BA SLG wOBA Whiff% K% PutAway % xBA xSLG xwOBA Hard Hit %
2025 Cutter 2.4 4 182 31.3 54 .227 .273 .281 20.2 11.1 16.2 .255 .310 .301 26.8
2025 Sweeper -1.5 -2 120 20.7 27 .269 .423 .313 25.5 40.7 19.6 .216 .370 .266 33.3
2025 4-Seam Fastball -3.2 -4 115 19.8 31 .308 .654 .450 27.4 25.8 17.0 .214 .442 .345 44.4
2025 Sinker 1.1 1 89 15.3 23 .273 .318 .280 16.7 17.4 20.0 .289 .355 .299 27.8
2025 Changeup -1.5 -1 69 11.9 13 .308 .462 .331 32.0 38.5 16.1 .188 .265 .194 25.0
2025 Curveball 10.5 1 6 1.0 3 .000 .000 .000 25.0 33.3 25.0 .168 .191 .159 50.0
2024 4-Seam Fastball -1.0 -3 286 29.9 81 .250 .344 .362 23.0 24.7 17.9 .277 .480 .402 38.6
2024 Sweeper 2.3 6 260 27.2 61 .138 .224 .197 34.4 32.8 21.3 .125 .191 .164 15.8
2024 Cutter -0.6 -1 209 21.9 52 .277 .574 .390 21.9 11.5 22.2 .295 .522 .382 46.3
2024 Changeup -0.5 -1 200 20.9 44 .163 .465 .288 32.6 34.1 20.5 .213 .477 .301 17.9
! Note: Years are in reverse order.
! Note: To better align with other values, positive numbers (red) are good, and negative numbers (blue) are poor.

Spin Direction

Year Pitch Type Pitches MPH Active Spin % Total Movement (In.) Spin-Based Observed Deviation
2025 Changeup 69 83.1 95 19.0 3:00 3:00 0
2025 Cutter 182 91.8 57 8.5 12:15 11:30 45
2025 4-Seam Fastball 115 96.1 94 17.5 1:15 1:15 0
2025 Sinker 89 96.1 95 19.8 1:15 2:00 -45
2025 Sweeper 118 81.8 57 18.1 8:15 9:00 -45
2024 Changeup 200 83.6 94 18.9 3:00 3:15 -15
2024 Cutter 208 91.1 48 6.5 12:00 11:15 45
2024 4-Seam Fastball 286 96.5 95 17.6 1:15 1:15 0
2024 Sweeper 258 82.2 57 18.8 8:15 9:00 -45
! Note: Years are in reverse order.
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! Note: This table is showing data from the PITCHER perspective.
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Pitcher Arm Angle

! Note: Data is available from 2020 through the present.
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Statcast Pitching Run Value

Runs
Year Team PA Pitches Heart Shadow Chase Waste All
2022 59 222 1 1 -2 -1 -1
2023 43 181 2 2 -4 -1 -2
2024 238 957 -1 14 -8 -4 1
2025 151 582 3 1 -1 -3 -1
Player 491 1,942 6 18 -16 6 -2
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Plate Discipline

Season Pitches Zone % Zone Swing % Zone Contact % Chase % Chase Contact % Edge % 1st Pitch Strike % Swing % Whiff % Meatball % Meatball Swing %
2022 222 53.6 68.1 87.7 20.4 61.9 36.5 64.4 45.9 17.6 9.9 72.7
2023 181 42.5 61.0 76.6 26.0 74.1 42.5 46.5 40.9 23.0 7.2 61.5
2024 957 49.2 66.9 79.0 26.7 54.6 43.6 67.8 46.5 28.1 7.4 81.7
2025 582 51.7 66.1 81.4 31.3 65.9 44.8 69.5 49.3 23.3 6.2 83.3
Player 1,942 49.8 66.3 80.7 27.3 60.9 43.0 66.1 46.8 25.0 7.3 78.9
MLB 48.9 67.0 82.5 28.4 58.0 42.7 61.1 47.3 25.0 7.3 76.3
! Note: All figures in this table cover the period 2015-present.

Percentile Rankings

Year xwOBA /
xERA
xBA xSLG xISO xOBP Brl Brl% EV Hard
Hit%
K% BB% Whiff% Chase
Rate
FB
Velo
FB
Spin
CB
Spin
Extension
2022 63 29 79
2023 58 29 88
2024 37 67 32 14 37 54 12 87 95 70 13 70 26 87 30 92
2025 79 17 89
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Expected Home Runs

Adjusted

Year Team Avg HR Trot Actual HR xHR HR-xHR Doubters Mostly Gone No Doubters No Doubter %
2022 22.81 2 1.5 1 3 1 0 0.0
2023 -- 0 0.9 -1 2 1 0 --
2024 24.57 10 9.5 1 2 6 5 50.0
2025 23.64 3 2.7 0 0 2 1 33.3
Player 24.15 15 14.6 0 7 10 6 40.0
Note: xHR tells how many of this pitcher's batted balls allowed would have been out of other stadiums. The "Adjusted" view here accounts for different wall heights, distances and environmental effects using Statcast Park Factor data.
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Expected Home Runs by Park

Adjusted

Year HR
2022 2 2 2 0 1 2 2 1 0 1 1 2 1 1 1 1 1 1 2 1 2 3 2 3 1 1 2 2 3 1 1
2023 0 1 0 2 1 1 1 1 0 1 0 1 2 1 1 1 1 1 1 2 1 0 2 1 1 1 0 0 1 1 1
2024 10 11 8 11 9 9 11 10 9 8 8 9 12 9 8 9 8 8 11 11 11 9 11 11 10 8 9 9 11 8 8
2025 3 3 2 3 3 3 3 3 3 2 3 3 3 3 3 3 3 3 2 3 2 3 3 3 3 2 3 3 2 3 1
Player 15 17 12 16 14 15 17 15 12 12 12 15 18 14 13 14 13 13 16 17 16 15 18 18 15 12 14 14 17 13 11
Note: xHR tells how many of this pitcher's batted balls allowed would have been out of other stadiums. The "Adjusted" view here accounts for different wall heights, distances and environmental effects using Statcast Park Factor data.
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Year to Year Changes

2025 +/-   2024 +/-   2023 +/-   2022
Results
BA .261 +.053 .208 -.011 .219 -.040 .259
xBA .236 +.010 .226 +.001 .225 +.028 .197
OBP .333 +.030 .303 -.102 .405 +.100 .305
xOBP .311 -.008 .319 -.090 .409 +.160 .249
SLG .396 +.009 .387 +.012 .375 -.051 .426
xSLG .348 -.062 .410 +.029 .381 +.039 .342
ISO .134 -.045 .179 +.023 .156 -.011 .167
xISO .111 -.073 .184 +.028 .156 +.012 .144
BABIP .330 +.089 .241 -.028 .269 -.017 .286
wOBA .318 +.018 .300 -.057 .357 +.041 .316
xwOBA .291 -.026 .317 -.045 .362 +.102 .260
wOBACON .377 +.023 .354 +.047 .307 -.054 .361
xwOBACON .336 -.045 .381 +.066 .315 +.029 .286
BACON .350 +.059 .291 +.022 .269 -.049 .318
xBACON .317 -.001 .318 +.041 .277 +.034 .243
Statcast Hit Metrics
Hard Hit % 31.4 +0.3 31.1 -15.1 46.2 +21.2 25.0
Avg Exit Velocity 86.2 -1.0 87.2 -2.3 89.5 +4.5 85.0
Launch Angle Sweet-Spot % 37.3 +2.2 35.1 +4.3 30.8 +1.3 29.5
Barrel % 4.9 -5.0 9.9 +2.2 7.7 +0.9 6.8
Avg Launch Angle 13.5 +1.5 12.0 +3.3 8.7 -3.9 12.6
Statcast Bat Tracking
Bat Speed 70.8 +0.4 70.4 -1.1 71.5 -- --
Attack Angle -3° 10° +2° -- --
Ideal Attack Angle % 49.6 -1.3 50.9 +20.1 30.8 -- --
Attack Direction +5° -3° +1° -4° -- --
Swing Path - Tilt 33° +1° 32° -4° 36° -- --
Swing Length 7.1 -0.2 7.3 0.0 7.3 -- --
Statcast Pitch Metrics
Fastball Velocity 94.1 -0.1 94.2 +0.2 94.0 -0.6 94.6
Breaking Velocity 81.8 -0.4 82.2 -3.4 85.6 -0.1 85.7
Offspeed Velocity 83.1 -0.5 83.6 +1.3 82.3 +0.3 82.0
Batted Ball Results
Barrels 5 -10 15 +13 2 -1 3
Popup % 6.9 -0.4 7.3 +7.3 0.0 -9.1 9.1
Flyball % 24.5 0.0 24.5 -2.4 26.9 -4.9 31.8
Line Drive % 25.5 +5.0 20.5 +1.3 19.2 +5.6 13.6
Groundball % 43.1 -4.6 47.7 -6.1 53.8 +8.3 45.5
Pull % 39.2 +0.8 38.4 +3.8 34.6 -1.8 36.4
Straight Away % 32.4 -7.3 39.7 -2.6 42.3 +1.4 40.9
Opposite Field % 28.4 +6.5 21.9 -1.2 23.1 +0.4 22.7
Weak Contact % 7.8 +1.8 6.0 +2.2 3.8 -5.3 9.1
Pull Airball % 13.7 +0.5 13.2 +1.7 11.5 -9.0 20.5
Topped Contact % 31.4 -5.0 36.4 -2.1 38.5 +6.7 31.8
Under Contact % 28.4 +7.2 21.2 -9.6 30.8 -1.0 31.8
Flare/Burner Contact % 21.6 -0.3 21.9 +2.7 19.2 +5.6 13.6
Solid Contact % 5.9 +1.3 4.6 +4.6 0.0 -4.5 4.5
HR/FB % 12.0 -15.0 27.0 +27.0 0.0 -14.3 14.3
Popups 7 -4 11 +11 0 -4 4
Flyballs 25 -12 37 +30 7 -7 14
Line Drives 26 -5 31 +26 5 -1 6
Groundballs 44 -28 72 +58 14 -6 20
Plate Discipline
In Zone % 51.7 +2.5 49.2 +6.7 42.5 -11.1 53.6
Out of Zone % 48.3 -2.5 50.8 -6.7 57.5 +11.1 46.4
Edge % 44.8 +1.2 43.6 +1.1 42.5 +6.0 36.5
Zone Swing % 66.1 -0.8 66.9 +5.9 61.0 -7.1 68.1
Out of Zone Swing % 31.3 +4.6 26.7 +0.7 26.0 +5.6 20.4
In Zone Contact % 81.4 +2.4 79.0 +2.4 76.6 -11.1 87.7
Out of Zone Contact % 65.9 +11.3 54.6 -19.5 74.1 +12.2 61.9
Whiff % 23.3 -4.8 28.1 +5.1 23.0 +5.4 17.6
First Strike % 69.5 +1.7 67.8 +21.3 46.5 -17.9 64.4
First Pitch Swing % 35.1 +0.8 34.3 +13.4 20.9 -7.9 28.8
Swing % 49.3 +2.8 46.5 +5.6 40.9 -5.0 45.9
Meatball Swing % 83.3 +1.6 81.7 +20.2 61.5 -11.2 72.7
Meatball % 6.2 -1.2 7.4 +0.2 7.2 -2.7 9.9
Zone Swing & Miss % 18.6 -2.4 21.0 -0.3 21.3 +9.0 12.3
Out of Zone Swing & Miss % 34.1 -11.3 45.4 +19.5 25.9 -12.2 38.1
In Zone 301 -170 471 +394 77 -42 119
Out of Zone 281 -205 486 +382 104 +1 103
Edge 261 -156 417 +340 77 -4 81
In Zone Swings 199 -116 315 +268 47 -34 81
Out of Zone Swings 88 -42 130 +103 27 +6 21
In Zone Swing & Misses 37 -29 66 +56 10 0 10
Out of Zone Swing & Misses 30 -29 59 +52 7 -1 8
Basic
Pitches 582 -375 957 +776 181 -41 222
PA 152 -89 241 +198 43 -16 59
AB 134 -78 212 +180 32 -22 54
Hits 35 -9 44 +37 7 -7 14
Singles 23 -3 26 +24 2 -7 9
Doubles 9 +1 8 +3 5 +2 3
Triples 0 0 0 0 0 0 0
Home Runs 3 -7 10 +10 0 -2 2
Walks 12 -15 27 +19 8 +4 4
Strikeouts 35 -26 61 +55 6 -5 11
K% 23.0 -2.3 25.3 +11.3 14.0 -4.6 18.6
BB% 7.9 -3.3 11.2 -7.4 18.6 +11.8 6.8
HBP 3 +1 2 0 2 +2 0
Batted Balls 102 -49 151 +125 26 -18 44
Number of Fastballs 386 -109 495 +405 90 -15 105
Number of Offspeed 69 -131 200 +137 63 -24 87
Number of Breaking 6 +6 0 -25 25 -4 29
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Statcast Fielder Positioning

vs RHHvs LHH
YearAlignment TypePAwOBAPATotal%PATotal%
2022 Shifts 59 .316 32 4 12.5 27 22 81.5
2023 Shades 43 .357 19 0 0.0 24 7 29.2
2024 Shades 236 .294 132 13 9.8 104 51 49.0
2025 Shades 151 .318 82 6 7.3 69 36 52.2
! Note: Shifts are through the 2022 season, Shaded starting from the 2023 season, Shift: three or more infielders are on the same side of second base, Shade: positioned outside of their typical responsible slices of the field.
Learn more about how positioning is defined here

Pitch Tempo

Bases EmptyRunners On Base
SeasonTeamPitchesTempoFast %Slow %PitchesTempoFast %Slow %
2022 61 18.7 1.6% 1.6% 42 21.5 0.0% 0.0%
2023 38 16.5 10.5% 0.0% 44 20.8 0.0% 0.0%
2024 247 17.3 10.5% 0.4% 177 19.6 1.1% 2.3%
2025 131 16.6 14.5% 0.8% 108 19.2 0.9% 1.9%

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Pitch Distribution