Miami Marlins

William Kempner

Pitcher#71

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

MLB.com profile ↗

Career stats

Career pitching by level

Swipe for more

	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

Swipe for more

	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 July
v Cleveland Guardians
2.0 IP, 2 ER, 3 K, 0 BB
L
9 July
v Seattle Mariners
0.1 IP, 2 ER, 0 K, 2 BB
W
3 July
@ Athletics
1.0 IP, 0 ER, K, 0 BB
W
30 June
@ Nashville Sounds
1.0 IP, ER, K, 0 BB
L
27 June
v Memphis Redbirds
1.0 IP, 0 ER, 2 K, 2 BB
W
25 June
v Memphis Redbirds
1.0 IP, 0 ER, K, BB
W
23 June
v Memphis Redbirds
1.0 IP, 0 ER, K, BB
L
20 June
@ Durham Bulls
2.0 IP, 0 ER, K, BB
W
15 June
@ Philadelphia Phillies
2.1 IP, 0 ER, 2 K, 0 BB
L
10 June
v Arizona Diamondbacks
2.0 IP, 0 ER, 3 K, 2 BB
W

Stats from official league and public sports feeds. Updated hourly.

William Kempner | Lineball