Miami Marlins
William Kempner
Key facts
- Age
- 25
- Height
- 183 cm (6'0")
- Weight
- 101 kg (222 lb)
- Number
- #71
- Born
- 18 June 2001
- Birthplace
- San Jose, CA, USA
- Debut
- 5 May 2026
- Position
- Pitcher
- Bats / Throws
- Right / Right
- MLB debut
- 5 May 2026
- Drafted
- 2022
Official profile
Career stats
Career pitching by level
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| W | L | ERA | G | GS | SV | IP | H | ER | HR | BB | SO | WHIP | K/9 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MLB | 1 | 0 | 2.92 | 9 | 0 | 0 | 12.1 | 8 | 4 | 1 | 4 | 14 | 0.97 | 10.22 |
| AAA | 3 | 3 | 3.51 | 37 | 0 | 7 | 48.2 | 28 | 19 | 5 | 36 | 77 | 1.32 | 14.24 |
| AA | 3 | 1 | 1.40 | 17 | 0 | 0 | 25.2 | 14 | 4 | 0 | 17 | 33 | 1.21 | 11.57 |
| A+ | 4 | 4 | 2.97 | 42 | 0 | 6 | 60.2 | 47 | 20 | 5 | 23 | 86 | 1.15 | 12.76 |
| A | 1 | 3 | 4.96 | 17 | 7 | 1 | 32.2 | 27 | 18 | 1 | 19 | 35 | 1.41 | 9.64 |
| ROK | 1 | 0 | 2.70 | 2 | 0 | 0 | 3.1 | 4 | 1 | 0 | 2 | 5 | 1.80 | 13.50 |
| WIN | 0 | 0 | 7.36 | 4 | 0 | 0 | 3.2 | 2 | 3 | 0 | 3 | 7 | 1.36 | 17.18 |
Pitching by season
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| Team | Lvl | W | L | ERA | G | GS | SV | IP | H | ER | HR | BB | SO | WHIP | K/9 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2026 | Miami Marlins | MLB | 1 | 0 | 2.92 | 9 | 0 | 0 | 12.1 | 8 | 4 | 1 | 4 | 14 | 0.97 | 10.22 |
| 2026 | Jacksonville Jumbo Shrimp | AAA | 0 | 3 | 3.98 | 24 | 0 | 6 | 31.2 | 20 | 14 | 3 | 21 | 52 | 1.29 | 14.78 |
| 2025 | Jacksonville Jumbo Shrimp | AAA | 3 | 0 | 2.65 | 13 | 0 | 1 | 17.0 | 8 | 5 | 2 | 15 | 25 | 1.35 | 13.24 |
| 2025 | Pensacola Blue Wahoos | AA | 3 | 1 | 1.13 | 16 | 0 | 0 | 24.0 | 11 | 3 | 0 | 15 | 31 | 1.08 | 11.63 |
| 2025 | Beloit Sky Carp | A+ | 1 | 2 | 3.04 | 19 | 0 | 6 | 26.2 | 19 | 9 | 0 | 10 | 39 | 1.09 | 13.16 |
| 2024 | Scottsdale Scorpions | WIN | 0 | 0 | 7.36 | 4 | 0 | 0 | 3.2 | 2 | 3 | 0 | 3 | 7 | 1.36 | 17.18 |
| 2023 | Richmond Flying Squirrels | AA | 0 | 0 | 5.40 | 1 |
Recent games
- 11 Julyv Cleveland Guardians2.0 IP, 2 ER, 3 K, 0 BBL
- 9 Julyv Seattle Mariners0.1 IP, 2 ER, 0 K, 2 BBW
- 3 July@ Athletics1.0 IP, 0 ER, K, 0 BBW
- 30 June@ Nashville Sounds1.0 IP, ER, K, 0 BBL
- 27 Junev Memphis Redbirds1.0 IP, 0 ER, 2 K, 2 BBW
- 25 Junev Memphis Redbirds1.0 IP, 0 ER, K, BBW
- 23 Junev Memphis Redbirds1.0 IP, 0 ER, K, BBL
- 20 June@ Durham Bulls2.0 IP, 0 ER, K, BBW
- 15 June@ Philadelphia Phillies2.1 IP, 0 ER, 2 K, 0 BBL
- 10 Junev Arizona Diamondbacks2.0 IP, 0 ER, 3 K, 2 BBW
Stats from official league and public sports feeds. Updated hourly.