week 27
this weekHOLD
last weekHOLD
Isaac Mattson
data as of September 27, 2026·week 27
ON THE 15-DAY IL
Hold · wait & see skill near league average (6.22); hold and wait — key skill metric not yet stable enough to call.med 0.50 (narrative held for review)
ROSK 0WHIP 1.24ERA 3.70W 0–0SV 0
Mattson is a hold — too little data to call either way.
ROS projects K 15 YTD → 0 ROS, WHIP 1.47 YTD → 1.24 ROS. Stable, rosterable; no clear edge to exploit either way.
VS His Norm
- Walk %10.2%—−1.6% ▼vs his ~11.8% career norm
- Strikeout %20.5%—−0.3% ▼vs his ~20.9% career norm
Drivers
- xeraNOISEskill near league average (6.22)
metric · nowrolling trajectoryvs. leaguestabilized?
Hard-Hit % Allowed52.1%
lg avg 40.0% ▲+12.1%vs his norm —
121 / 50 BBE
Barrel % Allowed12.4%
lg avg 8.0% ▲+4.4%vs his norm —
121 / 60 BBE
xwOBA Allowed.374
lg avg .315 ▲+.059vs his norm —xwOBA Allowed is above the ~.315 league average — expect it to fall.
176 / 200 TBF
xERA6.22
lg avg 4.10 ▲+2.12vs his norm —xERA is above the ~4.10 league average — expect it to fall.
176 / 200 TBF
ERA5.35
lg avg 4.10 ▲+1.25vs his norm —ERA is above the ~4.10 league average — expect it to fall.
38.7 / 200 IP
Strikeout %20.5%
lg avg 22.0% ▼−1.5%vs his norm −0.3% ▼
176 / 70 TBF
Walk %10.2%
lg avg 8.0% ▲+2.2%vs his norm −1.6% ▼
176 / 170 TBF
BABIP Against.347
lg avg .295 ▲+.052vs his norm —BABIP Against is above the ~.295 league average — expect it to fall.
121 / 800 BIP
Swinging-Strike %10.4%
lg avg 11.0% ▼−0.6%vs his norm —
176 / 60 TBF
Chase %27.4%
lg avg 28.5% ▼−1.1%vs his norm —
176 / 60 TBF
Fastball Velo94.2 mph
lg avg 94.0 mph ▲+0.2 mphvs his norm —
728 / 50 PITCHES
5×5 ROS Outlook
rest of seasonWhere each category goes the rest of the way, and the skill that drives it. Tap a row to expand the full derivation.
statytdrosdriverconf
K% 20.5%→20.7%signal0 K — K% 20.5% (signal) held to career ~20.9% → projected 20.7% over ~0 remaining IP.
xERA 6.22noise3.70 ERA — xERA 6.22 (noise) blended 0% skill / 100% league 3.70 at 20 IP.
BB% 10.2% + contactsignal1.24 WHIP — a 10% walk rate plus BABIP-against 0.303 gives a 1.50 skill WHIP, blended 0…
run support + role0-0 W — wins ride run support and how deep he goes, not just skill.
role (setup)0 SV — role: setup, not in the save mix.
rosterdeep3.70 ERA, 1.24 WHIP
Every projection traces to a sabermetric input. The driver and confidence shown per row are always visible; tap any row to expand the full derivation.