Isaac Mattson

ActiveIL

Pittsburgh Pirates · Pitcher

Age 316' 2" · 214 lbsThrows Right

FBaseball Overview

At 30 years old, this veteran right-hander is operating as a depth starter and relief contributor for Pittsburgh, carrying modest strikeout production with 22 K through early 2026 action. His 3.60 ERA and 1.28 WHIP suggest some volatility compared to his impressive 2025 showing (2.45 ERA, 1.13 WHIP across 47.2 innings), indicating he may be settling into a smaller role or workload this season. Fantasy managers should view him as a speculative add for ERA and WHIP upside rather than a win producer, given his limited innings and lack of save opportunities in the Pirates' bullpen structure. The upside exists if he commands increased usage, but limited track record at this stage of his career makes him more of a streaming candidate than a locked-in roster piece.

MLB Pitching

Year	Team	G	W	L	ERA	WHIP	K	IP	BB
2021	Baltimore Orioles	4	0	0	6.23	2.31	3	4.1	5
2024	Pittsburgh Pirates	3	0	0	5.06	1.13	6	5.1	5
2025	Pittsburgh Pirates	44	3	3	2.45	1.13	45	47.2	19
2026	Pittsburgh Pirates	38	0	0	5.35	1.60	36	38.2	18
Career	Totals	89	3	3	3.94	1.38	90	96	47

Source: MLB Stats API · Multi-team seasons show combined totals — click to expand

Minor League Pitching

Year	Team	G	GS	W	L	SV	ERA	WHIP	K	IP	BB
2017	2 teams▼	20	0	1	0	7	1.44	0.96	47	31.1	11
2018	2 teams▼	25	11	7	4	2	3.82	1.27	85	94.1	31
2019	3 teams▼	37	0	6	3	1	2.33	1.01	110	73.1	27
2021	Norfolk Tides	18	0	0	2	2	6.23	1.73	24	17.1	6
2022	Norfolk Tides	19	0	1	0	0	6.62	1.81	14	17.2	20
2023	Wichita Wind Surge	21	1	3	1	0	3.62	1.21	42	32.1	24
2024	2 teams▼	37	3	7	2	4	3.17	1.30	89	71	38
2025	Indianapolis Indians	19	0	2	0	4	2.57	0.95	25	21.0	6
2026	Indianapolis Indians	15	1	3	0	0	1.33	1.13	24	20.1	9
Career	Totals	211	16	30	12	20	3.23	1.21	460	378.2	172

Source: MLB Stats API · Multi-team seasons show combined totals — click to expand

Game Log2026 MLB

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Advanced Stats2026 season · via Baseball Savant

Click for year to year changes

FB Velo94.2 mph

Avg Spin2222 rpm

Whiff %21.0%

K %20.5%

BB %10.2%

Hard Hit %52.1%

Barrel %12.4%

xERA6.18

xBA Against0.292

xSLG Against0.498

BA Against0.282

SLG Against0.436

What These Stats Mean

FB Velo — Average fastball velocity. Harder throwers generate more swings and misses, setting up every other pitch in their arsenal. Velocity is the foundation of strikeout upside.

Avg Spin — Average spin rate across all pitches. Higher spin creates more movement and makes pitches harder to square up — elite spinners run better strikeout and batting average against numbers.

Whiff % — Swings-and-misses per swing. The most direct measure of a pitcher's ability to miss bats and the best leading indicator of strikeout rate.

K % — Strikeout rate per batter faced. The core fantasy pitching stat — high K% means reliable strikeout totals that hold up even in shorter starts.

BB % — Walk rate per batter faced. The primary control metric. High BB% tanks ERA and WHIP and keeps baserunners on constantly. Elite starters typically run below 7%.

Hard Hit % — Percentage of batted balls hit 95 mph or harder against. Low hard-hit% means weak contact, protecting both ERA and the defense behind the pitcher.

Barrel % — Percentage of batted balls barreled against. The most direct home run predictor — low barrel% pitchers rarely give up long balls.

xERA — Expected ERA based on contact quality allowed, removing the effect of sequencing, luck, and defense. Better predictor of future ERA than ERA itself.

xBA Against — Expected batting average opponents should hit based on contact quality. A gap between xBA and actual BA indicates unsustainable luck in either direction.

xSLG Against — Expected slugging allowed based on contact quality. High xSLG against predicts future extra-base damage; low xSLG means the pitcher is genuinely suppressing power.

BA Against — Actual batting average opponents are hitting — a key WHIP component. Check xBA to see if the number is sustainable.

SLG Against — Actual slugging allowed. Captures hits, doubles, triples, and home runs — lower means the pitcher is limiting the power damage he gives up.

GB% — Ground ball rate. High GB% pitchers generate double plays, limit home runs, and keep the ball in the park — great for protecting ERA and WHIP ratios.

FB% — Fly ball rate. High FB% pitchers give up more air contact — dangerous when combined with high exit velocity, less so when contact is soft.

Loading player data...

Year

Team

ERA

WHIP

2021

Baltimore Orioles

6.23

2.31

4.1

2024

Pittsburgh Pirates

5.06

1.13

5.1

2025

Pittsburgh Pirates

2.45

1.13

47.2

2026

Pittsburgh Pirates

5.35

1.60

38.2

Career

Totals

3.94

1.38

Year

Team

ERA

WHIP

2017

2 teams▼

1.44

0.96

31.1

2018

2 teams▼

3.82

1.27

94.1

2019

3 teams▼

2.33

1.01

110

73.1

2021

Norfolk Tides

6.23

1.73

17.1

2022

Norfolk Tides

6.62

1.81

17.2

2023

Wichita Wind Surge

3.62

1.21

32.1

2024

2 teams▼

3.17

1.30

2025

Indianapolis Indians

2.57

0.95

21.0

2026

Indianapolis Indians

1.33

1.13

20.1

Career

Totals

211

3.23

1.21

460

378.2

172