MLB Daily DeltaWeek 25 · September 10, 2026
Engraved portrait of Martín Pérez
week 25
this weekSELL-HIGH
last weekSELL-HIGH

Martín Pérez

ATL·P
data as of September 10, 2026·week 25
Sell High luck-free xERA 4.75 is 1.50 above the ERA, regression coming — BABIP-against 0.256 suppressed and unstable, flattering the ERA; sell into the hype before regression.high 0.95
ROSK 9ERA 4.52WHIP 1.39W 0–1SV 0

Pérez is a sell-high — his ERA is running on BABIP luck.

His ERA sits at 3.25, but the number holding it down is his BABIP-against: .256 against a league average of .295. That stat needs around 800 balls in play to become reliable, and he has 370. The gap is luck, not skill. Strip it out and his expected ERA is 4.75 — fully 1.50 runs higher than the scoreboard. The underlying profile backs the regression: he strikes out just 18% of batters, walks 10.4%, and gets swings and misses on only 9.4% of his pitches, all worse than league average. His fastball averages 89.9 mph. The expected ERA has climbed as the sample has grown, which is the opposite of what you want. The surface number is going to give. Sell high. 9 K and a 4.52 ERA ROS make him streaming-only; sell the inflated line while the window's open.

VS His Norm

  • Walk %10.4%—+2.0% ▲vs his ~8.4% career norm
  • Strikeout %18.0%—+1.6% ▲vs his ~16.4% career norm

Drivers

  • babip_againstNOISEBABIP-against 0.256 suppressed and unstable — flattering the ERA
  • xeraSIGNALluck-free xERA 4.75 is 1.50 above the ERA — regression coming
metric · nowrolling trajectoryvs. leaguestabilized?
Hard-Hit % Allowed38.1%
38.1%*
lg avg 40.0% ▼−1.9%vs his norm —
370 / 50 BBE
Barrel % Allowed5.4%
5.4%*
lg avg 8.0% ▼−2.6%vs his norm —
370 / 60 BBE
xwOBA Allowed.334
believable since May 30.334*
lg avg .315 ▲+.019vs his norm —
521 / 200 TBF
xERA4.75
4.75*
lg avg 4.10 ▲+0.65vs his norm —
521 / 200 TBF
ERA3.25
3.25*
lg avg 4.10 ▼−0.85vs his norm —ERA is below the ~4.10 league average — expect it to rise.
124.7 / 200 IP
Strikeout %18.0%
norm18.0%*
lg avg 22.0% ▼−4.0%vs his norm +1.6% ▲
521 / 70 TBF
Walk %10.4%
norm10.4%*
lg avg 8.0% ▲+2.4%vs his norm +2.0% ▲
521 / 170 TBF
BABIP Against.256
.256*
lg avg .295 ▼−.039vs his norm —BABIP Against is below the ~.295 league average — expect it to rise.
370 / 800 BIP
Swinging-Strike %9.4%
9.4%*
lg avg 11.0% ▼−1.6%vs his norm —
521 / 60 TBF
Chase %26.9%
26.9%*
lg avg 28.5% ▼−1.6%vs his norm —
521 / 60 TBF
Fastball Velo89.9 mph
89.9 mph*
lg avg 94.0 mph ▼−4.1 mphvs his norm —
1985 / 50 PITCHES

5×5 ROS Outlook

rest of season

Where each category goes the rest of the way, and the skill that drives it. Tap a row to expand the full derivation.

statytdrosdriverconf
K% 18.0%→17.6%signal9 K — K% 18.0% (signal) tempered to career ~16.4% → projected 17.6% over ~12 remaining IP.
xERA 4.75signal4.52 ERA — xERA 4.75 (signal) blended 65% skill / 35% league 4.10 at 52 IP.
BB% 10.4% + contactsignal1.39 WHIP — a 10% walk rate plus BABIP-against 0.277 gives a 1.44 skill WHIP, blended 6…
run support + role0-1 W — wins ride run support and how deep he goes, not just skill.
role (starter)0 SV — role: starter, not in the save mix.
rosterdrop9 K ROS, 4.52 ERA

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.

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