ATH · P

Mason Barnett

Age 25 B/T R/R 6′0″, 218 lb USA MLB debut 2025

40-man FV 40 · #15 in org

The Athletics’ roster as it stands on the 40-man, off the 26-man (call-up depth)

Keystone Stuff 101 54th pct

2026 fWAR −0.6

Projected 2027 WAR 0.0 Keystone Marcel+ at 57 IP

Pitching · 2026 percentiles

vs. MLB pitchers with 500+ pitches · 909 pitches

Keystone Stuff 101

Keystone Location 93

Keystone Pitching 96

Run value (xRV) −0.85

Strikeout % 21.8%

Walk % 13.1%

Whiff % 22.3%

Chase % 26.6%

Fastball velo 94.9

Extension 6.1 ft

50.0 IP7.02 ERA6.66 FIP 55° arm2 SV

Arsenal & Pitch Lab

Movement normalized to arm side · Keystone Stuff by pitch

RHP · arm angle 55° · how to read

Pitch	Use	Velo	IVB	HB	Stuff	Loc	Whiff	xRV/100
Four-seam49% use	49%	94.9	15.1	+1.1	95	88	20%	−1.40
Slider18% use	18%	87.3	−2.4	−3.4	119	106	26%	+0.63
Sweeper15% use	15%	83.6	−4.2	−15.7	98	111	25%	−0.19
Curveball10% use	10%	79.0	−15.2	−8.7	94	98	14%	−1.45
Changeup8% use	8%	85.3	1.1	+9.3	109	88	36%	−1.26

Weak pitch to watch

Four-seam grades 95 with below-average expected results; his slider grades 119. The best case is against righties: the slider is worth +1.6 runs per 100 pitches more, 1.9 standard errors (99 and 210 pitches), short of the 2 needed. No mix change until it clears.

Most similar pitchers

Pitches like Barnett: same hand, shape, slot and mix

Similarity	Player	Stuff	’26 WAR	’27 proj	2027
58	Andre Pallante STL · ’98	97	2.7	1.9	Arb
50	Ben Brown CHC · ’99	100	2.0	1.9	Arb
49	Bryce Miller SEA · ’98	104	0.9	1.0	Club option $6.1M
47	Hunter Dobbins STL · ’99	92	0.4	1.0	—
45	Brandon Young BAL · ’98	92	1.6	1.1	Pre-arb

Same-handed pitchers nearest on fastball velocity and shape, arm angle, extension, pitch mix, secondary shapes, Stuff, whiff rate and workload. 2026 regulars only.

Pitch locations · 2026

Where each pitch finishes, by batter side

Four-seam 51%

40% zone

Curveball 16%

35% zone

Changeup 14%

24% zone

Slider 14%

49% zone

Where each pitch finishes, catcher’s view. The bar marks the batter’s side; the box is an average strike zone. Pitches with 40+ thrown to this side.

Contract & projection

Club control (RosterResource) · Keystone projected WAR

2027 0.0 WAR —

2028 0.0 WAR —

2029 0.0 WAR —

2030 0.0 WAR —

Contract Studio →

Minor leagues

MLB Stats API · public box-score data

SeasonLevel	Level	Team	Age	G	PA / IP	PA / IP ·Line
2026AAA	AAA	Las Vegas Aviators	25	14	66.1 IP	66.1 IP · 5.16 ERA · 16.8% K · 12.1% BB
2025AAA	AAA	Las Vegas Aviators	24	25	119 IP	119 IP · 6.13 ERA · 22.8% K · 11.9% BB

FanGraphs: FV 40 · ETA 2026. Public pitch tracking exists only at Triple-A and some Florida State League parks.