William Kempner

Ranked Prospect Active on MLB Roster ... Miami Marlins
High Level
MLB
Years
2020-2026 (2026-2026)
Proper Name
William McCullough Kempner
Positions
P (91)
Height / Weight
6-0 / 222
Bats / Throws
Right / Right
Birthdate
June 18,2001   Age:  24.351
High School
Valley Christian (San Jose,CA)
Colleges
Gonzaga University (Spokane,WA)
Signing Bonus
$ 525,000
MLB Debut
MLBAM ID
Retrosheet#
kempw001
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Prospect Rankings

CSV
Glossary
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yearsourcetypeteamrankview rankings
2023Baseball AmericaTeamSan Francisco Giants26View Rankings
2024Baseball AmericaTeamSan Francisco Giants28View Rankings
2024ESPNTeamSan Francisco Giants22View Rankings
2026Baseball AmericaTeamMiami Marlins25View Rankings
4 record(s)
Prospect rankings are available since 1990 and are based on pre-season rankings from various ranking sites.

Scouting Grades

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Glossary
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Player 20-80 scouting grades are available to TBC PREMIUM subscribers
1 record(s)

Pitching Statistics

CSV
Glossary
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yearteam nameleaguelevelmlb#agewleraggscgshogrgfsviphrerhrbbsowpbkhbwhiph9hr9bb9so9ra9so/bb
2020GonzagaWCCNCAA-1Fr2019107.3660006007.17761921012.188.591.2311.052.458.590.22
2021GonzagaWCCNCAA-1So2920333.101190020140.2312114329345061.486.860.666.427.524.651.17
2022GonzagaWCCNCAA-1So2921213.00880000036.0251512221483081.286.250.505.2512.003.752.29
2022ACL Giants BlackACLRkSFN1921102.7020002003.14110253001.8010.800.005.4013.502.702.50
2022San Jose GiantsCal2ASFN4821006.3532001005.26441460021.769.531.596.359.536.351.50
2023San Jose GiantsCal2ASFN1522134.671450094127.0211814015292051.337.000.005.009.676.001.93
2023Eugene EmeraldsNwst2A+SFN1922322.9123000239034.0281511513475051.217.411.323.4412.443.973.62
2023Richmond Flying SquirrelsEast2AASFN722005.4010001001.23110220003.0016.200.0010.8010.805.401.00
2025Beloit Sky CarpMidw2A+MIA2724123.04190001912626.219119010392131.096.410.003.3713.163.713.90
2025Pensacola Blue WahoosSou2AAMIA3224311.1316000166024.01143015311021.084.130.005.6311.631.502.07
2025Jacksonville Jumbo ShrimpIL2AAAMIA3424302.6513000132117.0855215251031.354.241.067.9413.242.651.67
2026Jacksonville Jumbo ShrimpIL2AAAMIA 25034.56190001910525.2151413316462031.215.261.055.6116.134.912.88
2026Miami MarlinsNLMLBMIA 25000.0030003103.12000040000.605.400.000.0010.800.000.00
Tot:MLB (1 yrs) MLB   000.0030001303.12000040000.605.400.000.0010.800.00
Tot:NL (1 yrs) NL   000.0030001303.12000040000.605.400.000.0010.800.00
Tot:Minors (4 yrs) Minors   12113.331107004310313165.011573611192230161231.256.270.605.0212.553.982.50
Tot:Rk (1 yrs) Rk   102.7020000203.14110253001.8010.800.005.4013.502.702.50
Tot:A (2 yrs) A   134.9617700410132.2272218119352071.417.440.285.239.646.061.84
Tot:A+ (2 yrs) A+   442.97420002142660.2472620523867181.156.970.743.4112.763.863.74
Tot:AA (2 yrs) AA   311.4017000617025.21454017331021.214.910.005.9611.571.751.94
Tot:AAA (2 yrs) AAA   333.80320001232642.2231918531713061.274.851.056.5414.984.012.29
Tot:College (3 yrs) College   643.4325170008184.06343326598490151.456.750.646.329.004.611.42
Avg:MLB - 162 Inning avg MLB   ðŸ”’🔒🔒🔒🔒🔒🔒🔒🔒🔒162🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒
Avg:Minors - 162 Inning avg Minors   ðŸ”’🔒🔒🔒🔒🔒🔒🔒🔒🔒162🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒
Avg:College - 162 Inning avg College   ðŸ”’🔒🔒🔒🔒🔒🔒🔒🔒🔒162🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒🔒
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College Summer Stats are not set to Merge in this grid. (PREMIUM Feature)

Other Pitching Statistics

CSV
Glossary
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yearteam nameleaguecategoryagewleraggscgshogrgfsviphrerhrbbsowpbkhbwhiph9hr9bb9so9ra9so/bb
2019Corvallis KnightsWest Coast LeagueCollege Summer18210.6116000160229.1143228364040.754.300.612.4511.050.924.50
2021Anchorage BucsAlaska Summer LeagueCollege Summer20202.88770000040.2351313011443041.137.750.002.439.742.884.00
2022San JoseMinor PlayoffsMinor_Playoffs21000.0010001101.00000110001.000.000.009.009.000.001.00
2022ACL Giants BlackMinor PlayoffsMinor_Playoffs21100.0020002201.10000020000.000.000.000.0013.500.000.00
2024Scottsdale ScorpionsArizona Fall LeagueAFL23007.3640004103.22330372001.364.910.007.3617.187.362.33
2025Miami MarlinsMLB Spring TrainingSpring24006.7540004102.23221141011.5010.123.373.3713.506.754.00
Tot:Minor_Playoffs (1 Yrs) Minor_Playoffs 100.0030003302.10000130000.430.000.003.8611.570.003.00
Tot:AFL (1 Yrs) AFL 007.3640001403.22330372001.364.910.007.3617.187.362.33
Tot:CollegeSummer (2 Yrs) CollegeSummer 411.9323700016270.0491615219807080.976.300.262.4410.292.064.21
Tot:Spring (1 Yrs) Spring 006.7540001402.23221141011.5010.123.373.3713.506.754.00

Talent Ratings

About Talent Ratings
StrikeoutsWalksHittableSO/BBvs PowerDurabilityTeam Success
753487528766.580