P | Seattle Mariners
Bats/Throws: R/R | 6' 4" 215 lbs | Age: 27
Draft: 2019 | Rd. 1, No. 20, Seattle Mariners | Elon University
W L ERA G GS SV IP SO WHIP
2023 13 10 3.35 31 31 0 190.2 172 1.04
2024 14 11 3.53 33 33 0 191 179 1.07
2025 10 8 4.21 23 23 0 126 137 1.19
4 Seasons 45 34 3.58 112 112 0 637.2 621 1.11
G W-L ERA IP SO WHIP
2023 31 13-10 3.35 190.2 172 1.04
2024 33 14-11 3.53 191 179 1.07
2025 23 10-8 4.21 126 137 1.19
4 Seasons 112 45-34 3.58 637.2 621 1.11
MLB Percentile Rankings
Movement Profile (Induced Break)
?

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 24 2092 382 34 8.9 6.3 89.3 111.5 11.3 31.4 .232 .379 .302 .284 .354 38.7 24.5 4.1 3.39 3.31
2023 25 2825 560 42 7.5 5.5 89.2 115.6 12.4 32.0 .262 .425 .284 .305 .382 40.9 22.7 2.5 3.35 3.90
2024 26 2967 568 46 8.1 5.9 89.0 113.9 14.8 30.5 .235 .395 .287 .287 .356 36.3 23.0 3.0 3.53 3.41
2025 27 2086 351 30 8.5 5.7 90.6 113.3 11.7 35.3 .252 .392 .300 .305 .384 43.9 26.1 5.5 4.21 3.88
Player 9970 1861 152 8.2 5.8 89.4 115.6 12.8 32.0 .246 .400 .292 .295 .369 39.6 23.9 3.6
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

Kirby relies on 6 pitches.
Four Seamer
(29.0%) ,
Slider
(27.4%) ,
Sinker
(26.7%) ,
Knuckle Curve
(12.1%) ,
Split Finger
(2.7%) ,
Changeup
(2.2%) ,


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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 46.3 53.7 25.7 21.2 6.8 31.4 40.3 28.3 18.1 20.7 7.6 13.4 19.6 20.7
2023 44.6 55.4 25.7 22.1 7.5 38.2 31.4 30.4 22.3 16.1 6.3 15.9 15.4 24.1
2024 42.8 57.2 26.6 21.3 9.3 33.1 36.6 30.3 21.1 16.5 5.1 12.0 20.1 25.2
2025 44.4 55.6 23.4 26.8 5.4 33.6 37.6 28.8 20.2 17.7 6.6 13.4 19.9 22.2
Player 44.4 55.6 25.5 22.6 7.5 34.4 36.0 29.6 20.7 17.5 6.2 13.7 18.5 23.4
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 3.1 35.3 24.1 22.3 5.8 8.9 6.3
2023 2.3 34.5 24.3 25.5 5.9 7.5 5.5
2024 3.3 33.1 27.8 21.7 5.8 8.1 5.9
2025 2.6 33.0 20.8 28.8 6.0 8.5 5.7
Player 2.8 34.0 24.7 24.3 5.9 8.2 5.8
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 4-Seam Fastball SEA R 604 96.2 16.2 -2.1 10.1ARM 2.3 13.4 -2.4 10.1ARM 2.5
2025 Sinker SEA R 556 96.2 20.7 -0.8 16.7ARM 1.3 9.0 -1.6 16.7ARM 1.6
2025 Split-Finger SEA R 56 86.0 35.4 1.7 11.5ARM -0.1 1.6 1.4 11.5ARM 0.3
2025 Curveball SEA R 253 84.4 51.4 3.4 9.5GLV 2.1 -12.7 2.8 9.5GLV 0.4
2025 Slider SEA R 571 87.2 39.3 5.1 10.7GLV 6.3 -3.1 4.8 10.7GLV 6.1
2025 Changeup SEA R 46 87.8 29.6 -2.3 15.5ARM 1.0 5.9 -1.8 15.5ARM 1.1
2024 Curveball SEA R 242 83.3 53.8 5.4 8.6GLV 1.2 -14.1 4.1 8.6GLV -0.8
2024 Sinker SEA R 703 96.0 18.1 -2.6 15.8ARM 0.9 11.6 -4.4 15.8ARM 0.9
2024 Changeup SEA R 1 85.4 38.4 6.2 9.0ARM -5.1 -1.0 5.9 9.0ARM -5.2
2024 Split-Finger SEA R 301 86.0 35.6 2.3 9.6ARM -1.0 1.4 1.2 9.6ARM -1.1
2024 4-Seam Fastball SEA R 1006 96.0 13.9 -0.2 9.3ARM 1.9 15.8 0.1 9.3ARM 1.7
2024 Knuckleball SEA R 1 73.9 43.3 -10.3 2.6ARM 2.2 7.5 -10.4 2.6ARM 2.8
2024 Cutter SEA R 11 92.3 23.6 -0.6 1.0GLV -1.2 8.5 0.2 1.0GLV -1.7
2024 Slider SEA R 702 87.2 38.4 4.4 7.7GLV 3.6 -2.6 4.3 7.7GLV 2.9
! 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 4-Seam Fastball 1.2 7 604 29.0 154 .188 .319 .267 30.7 33.1 23.4 .217 .362 .295 41.4
2025 Slider 1.0 6 571 27.4 127 .258 .350 .263 31.2 26.0 18.2 .238 .369 .269 43.5
2025 Sinker -0.7 -4 556 26.7 158 .309 .518 .388 11.2 17.1 21.8 .292 .457 .358 43.5
2025 Curveball -0.4 -1 253 12.1 64 .254 .349 .270 38.6 32.8 19.3 .253 .364 .271 50.0
2025 Split-Finger -5.3 -3 56 2.7 12 .364 .636 .525 36.7 25.0 13.0 .382 .544 .424 75.0
2025 Changeup 2.7 1 46 2.2 9 .111 .111 .100 9.5 22.2 15.4 .162 .175 .147 14.3
2024 4-Seam Fastball 0.5 5 1,006 33.9 267 .221 .458 .303 29.1 30.7 21.2 .218 .439 .293 36.8
2024 Sinker 1.3 9 703 23.7 208 .266 .362 .302 10.5 12.0 13.5 .261 .381 .296 39.7
2024 Slider 1.4 10 702 23.7 162 .226 .316 .253 27.1 22.8 22.6 .236 .387 .287 32.5
2024 Split-Finger -2.0 -6 301 10.1 81 .253 .413 .323 29.0 24.7 14.8 .230 .369 .284 33.3
2024 Curveball -1.6 -4 242 8.2 58 .321 .411 .350 28.8 24.1 12.6 .235 .322 .257 35.7
2024 Cutter 0.6 0 11 0.4 1 .000 .000 .000 0.0 0.0 0.0 .040 .054 .039 0.0
2024 Knuckleball -3.8 0 1 0.0 -- -- -- -- -- -- -- -- -- --
2024 Changeup 5.1 0 1 0.0 -- -- -- 100.0 -- -- -- -- -- --
! 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 45 87.8 96 17.0 2:00 2:30 -30
2025 4-Seam Fastball 584 96.1 90 16.6 1:30 1:15 15
2025 Split-Finger 51 85.9 90 12.4 2:30 3:00 -30
2025 Knuckle Curve 230 84.2 81 18.0 7:15 7:00 15
2025 Sinker 533 96.2 87 19.2 1:30 2:15 -45
2025 Slider 540 87.1 52 12.6 7:15 8:15 -60
2024 Cutter 11 92.3 55 7.8 12:30 11:45 45
2024 4-Seam Fastball 996 96.0 94 18.1 1:15 1:00 15
2024 Split-Finger 242 86.0 87 10.7 2:15 3:00 -45
2024 Knuckle Curve 242 83.3 82 19.1 7:15 7:00 15
2024 Sinker 692 96.0 91 19.8 1:15 2:00 -45
2024 Slider 696 87.2 41 9.5 7:15 8:00 -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 542 2,092 4 10 -9 -5 0
2023 756 2,825 24 16 -8 -5 26
2024 777 2,967 8 31 -15 -10 15
2025 524 2,086 2 21 -11 -6 6
Player 2,599 9,970 38 78 -43 38 47
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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 2,092 55.1 71.9 81.4 29.0 71.1 45.5 67.7 52.6 21.2 8.7 84.1
2023 2,825 56.8 70.9 82.8 32.9 60.9 45.2 69.5 54.5 22.9 8.6 77.9
2024 2,967 52.0 73.2 82.1 31.9 60.7 44.7 66.3 53.4 24.1 7.9 83.4
2025 2,086 49.9 68.4 82.9 29.8 51.4 44.0 64.7 49.0 26.7 7.1 75.2
Player 9,970 53.6 71.3 82.3 31.1 60.7 44.9 67.2 52.6 23.6 8.1 80.4
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 71 56 50 46 86 13 22 28 44 63 96 15 45 72 40 11 69
2023 60 25 32 47 83 9 58 43 38 43 100 27 88 85 45 30 47
2024 75 55 45 35 92 3 41 42 70 50 99 39 84 80 44 42 58
2025 55 32 50 61 64 30 47 14 21 76 89 61 68 80 45 20 55
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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 24.32 13 13.2 0 14 14 3 23.1
2023 22.76 22 21.2 1 12 18 8 36.4
2024 25.01 22 21.6 0 8 15 11 50.0
2025 24.32 19 15.0 4 9 8 9 47.4
Player 24.06 76 71.0 5 43 55 31 40.8
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 13 9 12 16 14 13 16 9 8 9 9 18 16 11 15 18 14 10 11 15 11 13 24 15 8 8 18 20 13 13 11
2023 22 18 17 22 25 21 23 19 21 18 20 19 20 19 24 23 23 20 20 27 18 20 33 25 17 16 21 22 22 22 21
2024 22 23 19 23 20 23 25 21 17 15 21 23 24 19 22 19 20 19 23 23 25 23 28 26 17 21 21 21 25 21 22
2025 19 17 11 13 16 15 12 16 13 11 12 14 17 23 16 12 19 16 14 17 16 13 15 17 15 15 12 16 18 14 13
Player 76 67 59 74 75 72 76 65 59 53 62 74 77 72 77 72 76 65 68 82 70 69 100 83 57 60 72 79 78 70 67
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 .252 +.007 .245 -.001 .246 -.018 .264
xBA .252 +.017 .235 -.027 .262 +.030 .232
OBP .300 +.028 .272 +.002 .270 -.029 .299
xOBP .303 +.037 .266 -.020 .286 +.016 .270
SLG .392 -.001 .393 -.002 .395 +.002 .393
xSLG .392 -.003 .395 -.030 .425 +.046 .379
ISO .140 -.009 .149 .000 .149 +.020 .129
xISO .141 -.019 .160 -.003 .163 +.017 .146
BABIP .315 +.023 .292 -.001 .293 -.039 .332
wOBA .300 +.013 .287 +.003 .284 -.018 .302
xwOBA .305 +.018 .287 -.018 .305 +.021 .284
wOBACON .377 +.021 .356 +.002 .354 -.026 .380
xwOBACON .384 +.028 .356 -.026 .382 +.028 .354
BACON .345 +.025 .320 -.001 .321 -.033 .354
xBACON .350 +.039 .311 -.031 .342 +.029 .313
Statcast Hit Metrics
Hard Hit % 43.9 +7.6 36.3 -4.6 40.9 +2.2 38.7
Avg Exit Velocity 90.6 +1.6 89.0 -0.2 89.2 -0.1 89.3
Launch Angle Sweet-Spot % 35.3 +4.8 30.5 -1.5 32.0 +0.6 31.4
Barrel % 8.5 +0.4 8.1 +0.6 7.5 -1.4 8.9
Avg Launch Angle 11.7 -3.1 14.8 +2.4 12.4 +1.1 11.3
Statcast Bat Tracking
Bat Speed 71.7 +0.6 71.1 -0.5 71.6 -- --
Attack Angle -- --
Ideal Attack Angle % 50.8 -0.7 51.5 +2.0 49.5 -- --
Attack Direction -1° -1° -- --
Swing Path - Tilt 32° +2° 31° -1° 32° -- --
Swing Length 7.1 0.0 7.1 0.0 7.1 -- --
Statcast Pitch Metrics
Fastball Velocity 96.2 +0.2 96.0 0.0 96.0 +2.0 94.0
Breaking Velocity 86.3 +0.1 86.2 +1.6 84.6 +1.9 82.7
Offspeed Velocity 86.8 +0.8 86.0 +0.7 85.3 -0.7 86.0
Batted Ball Results
Barrels 30 -16 46 +4 42 +8 34
Popup % 5.4 -3.9 9.3 +1.8 7.5 +0.7 6.8
Flyball % 23.4 -3.2 26.6 +0.9 25.7 0.0 25.7
Line Drive % 26.8 +5.5 21.3 -0.8 22.1 +0.9 21.2
Groundball % 44.4 +1.6 42.8 -1.8 44.6 -1.7 46.3
Pull % 33.6 +0.5 33.1 -5.1 38.2 +6.8 31.4
Straight Away % 37.6 +1.0 36.6 +5.2 31.4 -8.9 40.3
Opposite Field % 28.8 -1.5 30.3 -0.1 30.4 +2.1 28.3
Weak Contact % 2.6 -0.7 3.3 +1.0 2.3 -0.8 3.1
Pull Airball % 13.4 +1.4 12.0 -3.9 15.9 +2.5 13.4
Topped Contact % 33.0 -0.1 33.1 -1.4 34.5 -0.8 35.3
Under Contact % 20.8 -7.0 27.8 +3.5 24.3 +0.2 24.1
Flare/Burner Contact % 28.8 +7.1 21.7 -3.8 25.5 +3.2 22.3
Solid Contact % 6.0 +0.2 5.8 -0.1 5.9 +0.1 5.8
HR/FB % 18.3 +3.7 14.6 -0.7 15.3 +2.0 13.3
Popups 19 -34 53 +11 42 +16 26
Flyballs 82 -69 151 +7 144 +46 98
Line Drives 94 -27 121 -3 124 +43 81
Groundballs 156 -87 243 -7 250 +73 177
Plate Discipline
In Zone % 49.9 -2.1 52.0 -4.8 56.8 +1.7 55.1
Out of Zone % 50.1 +2.1 48.0 +4.8 43.2 -1.7 44.9
Edge % 44.0 -0.7 44.7 -0.5 45.2 -0.3 45.5
Zone Swing % 68.4 -4.8 73.2 +2.3 70.9 -1.0 71.9
Out of Zone Swing % 29.8 -2.1 31.9 -1.0 32.9 +3.9 29.0
In Zone Contact % 82.9 +0.8 82.1 -0.7 82.8 +1.4 81.4
Out of Zone Contact % 51.4 -9.3 60.7 -0.2 60.9 -10.2 71.1
Whiff % 26.7 +2.6 24.1 +1.2 22.9 +1.7 21.2
First Strike % 64.7 -1.6 66.3 -3.2 69.5 +1.8 67.7
First Pitch Swing % 36.3 -1.9 38.2 +0.7 37.5 -1.1 38.6
Swing % 49.0 -4.4 53.4 -1.1 54.5 +1.9 52.6
Meatball Swing % 75.2 -8.2 83.4 +5.5 77.9 -6.2 84.1
Meatball % 7.1 -0.8 7.9 -0.7 8.6 -0.1 8.7
Zone Swing & Miss % 17.1 -0.8 17.9 +0.7 17.2 -1.4 18.6
Out of Zone Swing & Miss % 48.6 +9.3 39.3 +0.2 39.1 +10.2 28.9
In Zone 1,041 -501 1,542 -62 1,604 +452 1,152
Out of Zone 1,045 -380 1,425 +204 1,221 +281 940
Edge 918 -407 1,325 +48 1,277 +325 952
In Zone Swings 712 -417 1,129 -9 1,138 +310 828
Out of Zone Swings 311 -144 455 +53 402 +129 273
In Zone Swing & Misses 122 -80 202 +6 196 +42 154
Out of Zone Swing & Misses 151 -28 179 +22 157 +78 79
Basic
Pitches 2,086 -881 2,967 +142 2,825 +733 2,092
PA 524 -254 778 +21 757 +215 542
AB 480 -260 740 +13 727 +216 511
Hits 121 -60 181 +2 179 +44 135
Singles 85 -33 118 -4 122 +25 97
Doubles 20 -18 38 +10 28 +5 23
Triples 1 -2 3 -4 7 +5 2
Home Runs 15 -7 22 0 22 +9 13
Walks 29 +6 23 +4 19 -3 22
Strikeouts 137 -42 179 +7 172 +39 133
K% 26.1 +3.1 23.0 +0.3 22.7 -1.8 24.5
BB% 5.5 +2.5 3.0 +0.5 2.5 -1.6 4.1
HBP 7 0 7 +1 6 +1 5
Batted Balls 351 -217 568 +8 560 +178 382
Number of Fastballs 1,160 -560 1,720 -1 1,721 +261 1,460
Number of Offspeed 102 -200 302 +80 222 +55 167
Number of Breaking 824 -120 944 +64 880 +415 465
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Statcast Fielder Positioning

vs RHHvs LHH
YearAlignment TypePAwOBAPATotal%PATotal%
2022 Shifts 542 .302 258 61 23.6 284 165 58.1
2023 Shades 756 .284 403 32 7.9 353 192 54.4
2024 Shades 776 .288 421 72 17.1 355 213 60.0
2025 Shades 496 .287 231 29 12.6 265 116 43.8
! 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 566 16.5 28.1% 0.7% 310 25.3 0.0% 12.6%
2023 793 16.2 27.2% 0.1% 353 21.3 0.0% 0.6%
2024 818 17.3 5.0% 0.7% 384 20.6 0.0% 1.0%
2025 602 16.6 16.8% 0.3% 277 19.9 0.4% 0.4%

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Pitch Distribution