BOS · P

Aroldis Chapman

Age 38 B/T L/L 6′4″, 235 lb Cuba MLB debut 2010

40-man

Boston’s roster as it stands late-inning relief · 46 IP · 1.0 WAR in the role
Trade read Unlikely to be traded: BOS expects to contend (76% playoff odds) and he’s one of its best relievers.

Keystone Stuff 128 99th pct

2026 fWAR 1.6

Projected 2027 WAR 0.7 at 33 IP · 1.0 in his 2027 role

Pitching · 2026 percentiles

vs. MLB pitchers with 500+ pitches · 841 pitches

Keystone Stuff 128

Keystone Location 96

Keystone Pitching 120

Run value (xRV) +1.40

Strikeout % 33.3%

Walk % 10.8%

Whiff % 30.4%

Chase % 33.1%

Fastball velo 97.4

Extension 7.2 ft

51.2 IP1.92 ERA2.50 FIP 53° arm35 SV

Arsenal & Pitch Lab

Movement normalized to arm side · Keystone Stuff by pitch

LHP · arm angle 53° · how to read

Pitch	Use	Velo	IVB	HB	Stuff	Loc	Whiff	xRV/100
Four-seam37% use	37%	96.9	17.8	+2.2	115	92	18%	−1.04
Sinker32% use	32%	98.0	16.1	+10.8	120	100	31%	+2.22
Slider18% use	18%	85.9	5.2	−10.4	128	108	47%	+3.19
Splitter12% use	12%	90.2	3.0	+5.7	116	91	41%	+3.92

No mix change or new pitch clears its bar. The arsenal is efficient for its shapes.

Most similar pitchers

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

Similarity	Player	Stuff	’26 WAR	’27 proj	2027
24	Mason Montgomery PIT · ’00	110	2.2	1.2	Pre-arb
15	Brent Headrick NYY · ’97	101	2.1	1.2	Pre-arb
15	Adrian Morejon SD · ’99	132	2.8	1.9	Free agent
11	Jacob Latz TEX · ’96	113	2.2	1.1	Arb
11	José Alvarado PHI · ’95	112	0.6	0.4	Free agent

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 37%

50% zone

Sinker 35%

49% zone

Splitter 16%

29% zone

Slider 11%

37% 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 0.7 WAR Vesting option $13.0M

2028 0.5 WAR Free agent

2029 0.4 WAR Free agent

2030 0.3 WAR Free agent

Contract Studio →