Players · B · Pitcher · 2026 regular season

Mason Barnett

Age: 26
B/T: R/R
Height: 6' 0"
Weight: 218 lb
Number: #63

Born: November 7, 2000 in Kennesaw, GA, United States
MLB debut: August 30, 2025
Drafted: 2022, round 3
College: Auburn
High school: Cartersville

Compare with…vs Matt Strahm vs Tony Santillan vs Justin Lawrence

dbWAR: -.8
IP: 50.0
ERA: 7.02
FIP: 6.66
K/9: 9.0
FIP−: 159

Mason Barnett is a relief pitcher for the Athletics. In 2026 he struck out 50 batters over 50.0 innings across 20 appearances, going 1-4. His ERA of 7.02 was 67.9% higher than the league average of 4.18 — the worst on his team, and 528th of 539 among MLB pitchers with 20+ innings. Stripping out defence, his 6.66 FIP suggests he pitched better than his ERA shows. He missed bats on 22.3% of swings (9.7% of every pitch he threw), walked 13.1% of the batters he faced and struck out 21.8%. His -0.9 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 regular season.

FIP6.66

K/99.0

WHIP1.66

WAR-.9

WAR by season

Pitching Regular season

Standard and advanced, by season. Regular-season games only.

																				Trend
2026	ATH	20	6	50.0	1	4	2	53	39	50	30	7.02	6.66	1.66	9.0	5.4	168	159	-0.9
2025	ATH	5	5	22.1	1	1	0	26	17	18	11	6.85	4.88	1.66	7.3	4.4	165	117	0.1

Platoon splits

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

Season

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	120	101	30	6	18	18	.297	.400	.535	.404	15.0%
vs RHB	109	95	23	8	12	32	.242	.339	.516	.372	29.4%

Pitch sequencing

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

ShowBatter

Four-seamSliderSweeperCurveballChangeup

Select a count to see exactly what Mason Barnett throws in it.

Pitch arsenal

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

Season


Four-Seam Fastball	49.2%	447	94.9	2,229	42.1%	19.8%	98	.276	.920
Slider	17.8%	162	87.3	2,503	53.7%	26.3%	29	.241	.767
Sweeper	15.2%	138	83.6	2,685	46.4%	24.6%	34	.235	.765
Curveball	10.2%	93	79.0	2,697	38.7%	13.5%	21	.333	1.036
Changeup	7.6%	69	85.3	992	29.0%	36.0%	15	.267	.933

Mason Barnett'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.

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Similar players

Nearest 2026 seasons by command, run prevention and role, on rate statistics rather than totals.

Tony SantillanCIN

ERA: 6.42
FIP: 7.06
SO: 36
WAR: -1.1

Alex LangeKC

ERA: 6.75
FIP: 5.87
SO: 60
WAR: -0.7

Kodai SengaNYM

ERA: 7.34
FIP: 5.83
SO: 75
WAR: -0.7

Ronel BlancoHOU

ERA: 6.68
FIP: 6.37
SO: 29
WAR: -0.5

Comparable

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.