MLB · P · Miami Marlins
William Kempner
B/T R/R · 6' 0" · 222 lb · born San Jose, CA, USA · age 25 · draft 2022 rd 3 · MLB debut 2026-05-05
Scout’s note
William Kempner is a 25-year-old right-hander from San Jose who reached Miami last May out of the 2022 third round. He has 14 strikeouts across 9 career appearances, 3 of them in his last two games.
Collect William Kempner
If the signal is right, the cardboard usually finds out later. Current listings:
William Kempner cards on eBay →Paid link — as an eBay Partner, FVR earns from qualifying purchases.
Not financial advice. We take positions only after publication — never before. Misses stay on the record.
Umpire favor
+0.5 net runs over 4 graded games — the zone was kind to him on balance.
The line
Last 14 days (through 2026-07-20): 2 G · 2.1 IP · 15.43 ERA · 3 SO · 3.00 WHIP
Bio & season lines: MLB StatsAPI · refreshed nightly · abbreviations →