DataBaseball
2026
Jhonathan Díaz headshot

Pitcher · 2025

Jhonathan Díaz

Age
29
B/T
L/L
Height
6' 0"
Weight
170 lb
Born
September 13, 1996 in Valencia, Venezuela
MLB debut
September 17, 2021
dbWAR
-.0
2 season(s)
IP
1.1
ERA
0.00
FIP
1.64
K/9
6.8
FIP−
39
100 = avg

Jhonathan Díaz is a relief pitcher for the Seattle Mariners. In 2025 he struck out 1 batter over 1.1 innings across 1 appearance, going 0-0. His ERA of 0.00 was 100.0% lower than the league average of 4.16. Stripping out defence, his 1.64 FIP suggests that his ERA had some help behind him. He missed bats on 14.3% of swings (7.7% of every pitch he threw), walked 0.0% of the batters he faced and struck out 20.0%. His 0.0 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, 2025.

FIP1.64
K/96.8
WHIP0.75
WAR.0

Platoon splits

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

Opponent batting by the side the hitter bats from, 2025. Counted from play-by-play, so totals can differ from the box-score season line by a plate appearance or two.
SplitPAABHHRBBSOAVGOBPSLGwOBAK%
vs LHB221000.500.500.500.4430.0%
vs RHB330001.000.000.000.00033.3%

Pitch sequencing

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

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SliderCurveballChangeup

Select a count to see exactly what Jhonathan Díaz throws in it.

Pitch arsenal

What he throws, how hard, and how often it misses in 2025.

Slider46.2%1278.52,77358.3%14.3%
Jhonathan Díaz'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.

Pitching

Standard and advanced, by season.

Trend
2025101.100010100.001.640.756.80.00390.0
2024519.2010145834.665.131.767.42.8114126-0.1

Head to head

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Jhonathan Díaz
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.