MLB Daily DeltaWeek 17 · July 18, 2026
Engraved portrait of Martín Pérez
week 17
this weekSELL-HIGH
last weekSELL-HIGH

Martín Pérez

ATL·P
data as of July 18, 2026·week 17
ON THE 15-DAY IL
Sell High luck-free xERA 4.58 is 1.04 above the ERA, regression coming — BABIP-against 0.243 suppressed and unstable, flattering the ERA; sell into the hype before regression.high 0.95
ROSK 41ERA 4.41WHIP 1.37W 2–4SV 0

Pérez is a sell-high — ERA built on BABIP luck, xERA rising.

Martín Pérez's ERA is 3.54, which looks fine, but that number is being held down by a BABIP-against of .243 — 52 points below the league average of .295, and his sample of 237 balls in play is a fraction of the 800 needed for that stat to be reliable. His expected ERA is 4.58, over a full run higher, and that gap has been widening across his last several starts, signaling that the luck is fading. His strikeout rate (18.6%) and walk rate (9.6%) are both worse than league average, leaving no elite skill to fall back on when the BABIP normalizes. The xERA is the skill; the ERA is the mirage. Sell high. 41 K, 4.41 ERA, 1.37 WHIP — a streaming-only arm, not a weekly hold. Sell before the ERA climbs.

VS His Norm

  • Strikeout %18.6%—+2.2% ▲vs his ~16.4% career norm
  • Walk %9.6%—+1.2% ▲vs his ~8.4% career norm

Drivers

  • babip_againstNOISEBABIP-against 0.243 suppressed and unstable — flattering the ERA
  • xeraSIGNALluck-free xERA 4.58 is 1.04 above the ERA — regression coming
metric · nowrolling trajectoryvs. leaguestabilized?
Hard-Hit % Allowed36.3%
36.3%*
lg avg 40.0% ▼−3.7%vs his norm —
237 / 50 BBE
Barrel % Allowed6.8%
6.8%*
lg avg 8.0% ▼−1.2%vs his norm —
237 / 60 BBE
xwOBA Allowed.330
.330*
lg avg .315 ▲+.015vs his norm —
333 / 200 TBF
xERA4.58
4.58*
lg avg 4.10 ▲+0.48vs his norm —
333 / 200 TBF
ERA3.54
3.54*
lg avg 4.10 ▼−0.56vs his norm —ERA is below the ~4.10 league average — expect it to rise.
81.3 / 200 IP
Strikeout %18.6%
norm18.6%*
lg avg 22.0% ▼−3.4%vs his norm +2.2% ▲
333 / 70 TBF
Walk %9.6%
norm9.6%*
lg avg 8.0% ▲+1.6%vs his norm +1.2% ▲
333 / 170 TBF
BABIP Against.243
.243*
lg avg .295 ▼−.052vs his norm —BABIP Against is below the ~.295 league average — expect it to rise.
237 / 800 BIP
Swinging-Strike %9.3%
9.3%*
lg avg 11.0% ▼−1.6%vs his norm —
333 / 60 TBF
Chase %26.2%
26.2%*
lg avg 28.5% ▼−2.3%vs his norm —
333 / 60 TBF
Fastball Velo90.0 mph
90.0 mph*
lg avg 94.0 mph ▼−4.0 mphvs his norm —
1282 / 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% 18.6%→17.8%signal41 K — K% 18.6% (signal) tempered to career ~16.4% → projected 17.8% over ~52 remaining…
xERA 4.58signal4.41 ERA — xERA 4.58 (signal) blended 65% skill / 35% league 4.10 at 52 IP.
BB% 9.6% + contactsignal1.37 WHIP — a 10% walk rate plus BABIP-against 0.280 gives a 1.40 skill WHIP, blended 6…
run support + role2-4 W — wins ride run support and how deep he goes, not just skill.
role (starter)0 SV — role: starter, not in the save mix.
rosterdrop41 K ROS, 4.41 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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