William Kempner
RP · Marlins
Injured List
A-
C+
N/A
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The Verdict on William, in One Read
On the field, William Kempner grades out as an excellent RP for Marlins (A- Performance). That places him 94th of 429 graded relief pitchers. The public read is mixed (C+ Sentiment), drawn from current news and social signal rather than the box score.
Career StatsA-
| Year | Team | GP | ERA | W-L | K | WHIP | IP | SV |
|---|---|---|---|---|---|---|---|---|
| Career |  | 9 | 2.9189188 | 1-0 | 14 | 0.972973 | 0.0 | 0 |
| 2026 | | 9 | 2.92 | 1-0 | 14 | 0.97 | 12.1 | 0 |
How William Compares at the Position
William Kempner ranks 94th of 429 graded relief pitchers by performance. That slots William between Hoby Milner (A-) just ahead and Antoine Kelly (B+) just behind.
Graded higher
Hoby MilnerCubsA-Drey JamesonDiamondbacksA-Yovanny CruzNationalsA-William KempnerA-
Graded lower
Antoine KellyCubsTransaction History
Marlins sign RHP William Kempner
il move · 7/12/2026
C
Marlins sign RHP William Kempner
roster move · 6/16/2026
C
Marlins sign RHPs William Kempner
roster move · 3/8/2026
C
Marlins sign RHP William Kempner
signing · 3/8/2026
C
Traded RHP William Kempner to Miami in exchange for future considerations. International Bonus Pool Money. Agreed to terms on minor league contracts with CF DJean Macares, RHPs Jose Gonzalez, Yesid Mendoza, Ebduar Loina, Jeremiah Jones and Abraham Utrera, LHP Winkel Del Rosario, SSs Josuar Gonzaelz, Yulian Barreto, Alexander Camacaro and Yeison Oviedo, Cs Diego Alambarrio, Carlos Martinez and Miguel Caraballo and LF Rainer Espinoza.
trade · 1/15/2025
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About this player
William Kempner is a player on the Marlins roster listed at RP for the Marlins. FanVerdicts covers every MLB player, team, GM, and transaction — and puts your verdict on all of it. Sign in to cast your Fan Verdict on William Kempner, see where the crowd lands, and argue the call. FanVerdicts also brings its own read — performance, sentiment, and Contract Value Index — as one honest input alongside the crowd's. Where FanVerdicts has weighed in so far: Performance A-, Sentiment C+.
The crowd's Fan Verdict moves in real time as fans vote on this profile. FanVerdicts' own read updates as new data lands — performance recalculates when MLB game stats post, sentiment shifts with media coverage and fan discussion, and the Contract Value Index recomputes when contract terms change.
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