Players · L · Pitcher · 2026

Seth Lonsway

San Francisco Giants National League West

Age: 28
B/T: L/L
Height: 6' 0"
Weight: 206 lb
Number: #86

Born: October 7, 1998 in St. Mary's, OH, United States
MLB debut: August 29, 2026
Drafted: 2017, round 19
College: Ohio State
High school: Celina

dbWAR: .1
IP: 2.0
ERA: 9.00
FIP: 1.10
K/9: 9.0
FIP−: 26

Seth Lonsway is a relief pitcher for the San Francisco Giants. In 2026 he struck out 2 batters over 2.0 innings across 1 appearance, going 0-0. His ERA of 9.00 is 114.9% higher than the league average of 4.19. Stripping out defence, his 1.10 FIP suggests he pitched better than his ERA shows. He missed bats on 20.0% of swings (9.1% of every pitch he threw), walked 0.0% of the batters he faced and struck out 18.2%. His 0.1 dbWAR is built from that FIP rather than runs allowed, so it credits him for what he controls and not for the defence behind him.

League context

Percentile among qualified pitchers, 2026.

FIP1.10

K/99.0

WHIP2.50

WAR.1

Pitching

Standard and advanced, by season.

																				Trend
2026	SF	1	0	2.0	0	0	0	5	2	2	0	9.00	1.10	2.50	9.0	0.0	215	26	0.1	—

Platoon splits

How left- and right-handed hitters fare against him.

Opponent batting by the side the hitter bats from, 2026. Counted from play-by-play, so totals can differ from the box-score season line by a plate appearance or two.
Split	PA	AB	H	HR	BB	SO	AVG	OBP	SLG	wOBA	K%
vs LHB	2	2	0	0	0	1	.000	.000	.000	.000	50.0%
vs RHB	9	9	5	0	0	1	.556	.556	.556	.497	11.1%

Pitch sequencing

What Seth Lonsway throws in each count, and what he follows each pitch with. Select any cell for the breakdown.

ShowBatter

SinkerCutterChangeup

Select a count to see exactly what Seth Lonsway throws in it.

Pitch arsenal

What he throws, how hard, how often it misses, and what hitters do with it.


Sinker	48.5%	16	91.6	1,881	43.8%	25.0%	2	—	—

Seth Lonsway's arsenal by usage. Velocity is average release speed in mph, spin in rpm, and whiff rate is misses per swing — the cleanest single measure of whether a pitch beats hitters. BAA and OPS are what hitters did against each pitch, credited to the one that ended the plate appearance, and are left blank under 15 at-bats.

Head to head

Put Seth Lonsway beside up to three others.

Compare — add up to 3 more players

Seth Lonsway

How these are computed

wOBA uses linear weights measured from this season's own play-by-play rather than published constants, and wRC+ is park-adjusted against that same league. dbWAR is our own open implementation — not fWAR or bWAR — and the full derivation, including its simplifications, is on the methodology page.