Isaac Mattson
RPQualifiedPittsburgh Pirates · NL · Age 31 · Bats R / Throws R · 32.7 IP · 141 BF
↓ Negative regressionSELLRank 72 of 617 pitchers by opportunity score
Opportunity Score
25
+5.6 last 7 days
HOLDProduction matches the underlying process.
Most likely driver: arm slot dropped — deliberate change or mechanical compensation (25% confidence).Mechanical flag: arm angle −3.4°.
W-L
0-0
SV
0
IP
32.7
K
29
BB
14
ERA
4.13
WHIP
1.38
Edge breakdown
Expected
What the batted-ball quality deserves
xERA5.71
xwOBA.362
xBA.277
xSLG.487
xBABIP.281
Actual
What the scoreboard says
ERA4.13
wOBA.315
BA.248
SLG.384
BABIP.281
Difference
Actual − expected · percentile of the gap
ERA vs xERA−1.5811
wOBA against vs xwOBA−.0477
BA against vs xBA−.02916
SLG against vs xSLG−.1033
BABIP against vs xBABIP+.00050
Arsenal & pitch shapes
2026 usage, velocity, and movement per pitch · dashed ring = league average for that pitch type · movement in inches, pitcher's perspective
| Pitch | Usage | Velo | vs 2025 | Velo pctl | Spin | IVB | HB |
|---|---|---|---|---|---|---|---|
| 4-Seam Fastball | 72.7%(−5.7) | 94.1lg 94.5 | +0.2 | 4074 | 2347 | 18.1"lg 15.4 | 9.5"lg 7.8 |
| Slider | 11.0%(+2.2) | 83.8lg 86.2 | −1.5 | 1627 | 2208 | 1.8"lg 1.5 | 3.6"lg 4.1 |
| Changeup | 9.6%(−2.0) | 85.9lg 86.6 | ±0.0 | 3793 | 1303 | 5.7"lg 4.1 | 10.0"lg 14.0 |
| SweeperNEW | 6.7% | 82.9lg 82.5 | — | 5569 | 2314 | -1.2"lg 0.9 | 10.5"lg 13.7 |
IVB = induced vertical break (rise vs gravity-only). HB = horizontal break. Velo percentile is against all pitchers throwing the same pitch type. Sources: Savant pitch arsenals & movement leaderboards.
Mechanics Watch
2026 in gold · 2025 dashed · thin ticks = league average
Arm Angle −3.4°
Arm slot
79 pctl · −3.4° vs prior
What this can't see: Joint kinetics, hip-shoulder separation, and kinematic sequencing (Hawkeye/KinaTrax, team-internal — never estimated here). Stance angle and foot separation (Savant visuals only, no export). Release extension (column exported empty; needs pitch-level ingest).
Recent games
Percentile rankings
xERA
16
xwOBA Against
16
K%
34
BB%
32
Whiff%
21
FB Velocity
43
Hard-Hit% Against
9
Spin Rate
66
30-day rolling trends
Rolling ERA vs xERA
ERAxERA
Rolling Hard-Hit% Against
Rolling FB Velocity
Rolling Stuff Index
Rolling Whiff%