MLB Player Intelligence

William Kempner

RP  ·  Miami Marlins  ·  #71

Bats/ThrowsR/R
Height6' 0"
Weight222 lbs
BirthplaceSan Jose, CA
MLB Debut2025
🩹 60-Day-IL — Elbow, Surgery, Right (expected back Wednesday, September 1, 2027)

📊Full Stat Line (2026)

G9
GS0
QS0
HLD0
H8
ER4
HR1
BB4
K/910.22
WAR0.18

🤚Career Splits by Handedness

vs Left-Handed Batters
AVG.238
OBP.333
SLG.476
OPS.810
24 PA  ·  Ranks #445 of 640 qualified pitchers

Career totals from real plate-appearance data — lower OPS allowed is better for a pitcher.

⚔️This Season vs. Each Opponent

Opponent ERAIPKBBOpp AVG
vs. NYM 0.002.130.222
vs. PHI 0.002.120.000
vs. ARI 0.002.032.000
vs. CLE 9.002.030.375
vs. TB 0.001.110.200
vs. BAL 0.001.010.000
vs. OAK 0.001.010.000
vs. SEA 54.000.102.667

🏟️This Season at Each Ballpark

Ballpark ERAIPKBBOpp AVG
Total 2.9212.1144.182
Marlins Park 5.406.284.240
Citi Field 0.002.130.222
Citizens Bank Park 0.002.120.000

📅By Month & Recent Form

Split ERAIPKBBOpp AVG
Last 7 Days 9.002.030.375
Last 15 Days 9.002.030.375
Last 30 Days 9.002.030.375
May 0.003.140.167
June 0.005.262.056
July 10.803.142.357

🎯Pitch Arsenal (2026)

Type Pitches Usage% Zone% Chase% Whiff% BA wOBA xwOBA
4-Seam Fastball 91 48.9% 41.8% 38.5% 35.9% .278 .445 .430
Sweeper 44 23.7% 40.9% 44.0% 40.0% .154 .278 .301
Sinker 25 13.4% 32.0% 50.0% 12.5% .000 .000 .250
Cutter 22 11.8% 54.5% 11.1% 44.4% .000 .000 .139
Changeup 4 2.1% 25.0% 0.0% 0.0% — — —

🌀Pitch Movement (2026)

Type # Velo Spin IVB H-Break Ext
4-Seam Fastball 26 95.4 2,381 +12.9" +1.4" 6.1
Sweeper 14 82.1 2,904 +6.2" -1.4" 6.1
Sinker 10 94.1 2,225 +4.3" +1.7" 6.1

IVB = induced vertical break (gravity removed) · H-Break = horizontal movement · Ext = release extension in feet.

📋Recent Game Log

DateOppScore IPHERBBKOutsERAPCDec
L Saturday, July 11, 2026 CLE 4-1 2.0320362.9242—
L Monday, June 15, 2026 PHI 0-7 2.1000270.0033—
W Wednesday, June 10, 2026 ARI 0-8 2.0002360.0036W
L Friday, June 5, 2026 TB 6-0 1.11001—0.0013—
L Sunday, May 31, 2026 NYM 1-10 1.1200340.0028—
L Saturday, May 30, 2026 NYM 1-6 1.0000030.0012—
L Tuesday, May 5, 2026 BAL 9-7 1.0000130.008—

👥Team — Miami Marlins

PlayerPosKey Stat
Deyvison De Los Santos 1B .143 AVG
Kyle Stowers 1B .239 AVG
Xavier Edwards 2B .280 AVG
Jared Serna 2B .214 AVG
Leo Jimenez 3B .199 AVG
Graham Pauley 3B .211 AVG
Javier Sanoja 3B 13.50 ERA
Logan Driscoll C —
Joe Mack C .234 AVG
Brian Navarreto C .135 AVG
Jakob Marsee CF .231 AVG
Agustin Ramirez DH .235 AVG
Heriberto Hernandez LF .228 AVG
Andrew Nardi Relief Pitcher 5.16 ERA
Owen Caissie RF .220 AVG
Griffin Conine RF .264 AVG
Esteury Ruiz RF .216 AVG
Austin Slater Right Fielder 0.00 ERA
Anthony Bender RP 2.62 ERA
Brandan Bidois RP 6.32 ERA
Bradley Blalock RP 5.56 ERA
Zach Brzykcy RP 3.00 ERA
Josh Ekness RP 3.23 ERA
Pete Fairbanks RP 6.31 ERA
Calvin Faucher RP 3.56 ERA
Dax Fulton RP 3.77 ERA
Cade Gibson RP 5.36 ERA
Wikelman Gonzalez RP 2.66 ERA
John King RP 3.99 ERA
Patrick Monteverde RP 9.00 ERA
Michael Petersen RP 3.02 ERA
Jack Ralston RP 5.71 ERA
Victor Vodnik RP 4.91 ERA
Joshua White RP 67.50 ERA
Tyler Zuber RP 5.67 ERA
Sandy Alcantara SP 3.87 ERA
Ryan Gusto SP 4.09 ERA
Janson Junk SP 4.22 ERA
Max Meyer SP 2.68 ERA
Eury Perez SP 3.91 ERA
Tyler Phillips SP 3.34 ERA
Maximo Acosta SS .204 AVG
Otto Lopez SS .305 AVG
Chris Paddack Starting Pitcher 6.79 ERA

See the Full Analysis

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