MLB Daily DeltaWeek 17 · July 18, 2026
Engraved portrait of Juan Mejia
week 17
this weekBUY-LOW
last weekBUY-LOW

Juan Mejia

COL·P
data as of July 18, 2026·week 17
Buy Low fastball velocity stable and above league, the arm is fine — luck-free xERA 4.19 is right around league, a usable arm the ERA is hiding; BABIP-against 0.339 elevated and unstable, bloating the ERA; buy the player, not the number.high 0.90
ROSK 26WHIP 1.26ERA 3.73W 1–1SV 2–3

Mejia is a buy-low — ERA is lying about the arm.

Mejia's ERA sits at 5.74, but the story is in the stats that hide it. His BABIP-against is .339, 44 points above the league average of .295. BABIP-against needs around 800 balls in play to be reliable; he has 123. That gap is luck, not a reflection of his pitching. Strip out the noise and his expected ERA is 4.19, right around league average — not glamorous, but a usable arm. His fastball velocity is 97.4 mph, well above the 94.0 mph league average, and it has been stepping up through the sample. His barrel rate allowed is 4.1% — half the league average of 8.0% — and that is a skill mark, stable at 123 batted balls. His strikeout rate is above league and his swinging-strike rate is elite. The ERA is ugly; the underlying skill is real. Buy low. 26 K and a 3.73 ERA with elite peripherals make him a deep-league buy before the surface catches up.

VS His Norm

  • Strikeout %23.0%—−2.3% ▼vs his ~25.3% career norm
  • Walk %11.5%—+0.9% ▲vs his ~10.6% career norm

Drivers

  • xeraNOISEluck-free xERA 4.19 is right around league — a usable arm the ERA is hiding
  • babip_againstNOISEBABIP-against 0.339 elevated and unstable — bloating the ERA
  • p_fastball_veloSIGNALfastball velocity stable and above league — the arm is fine
metric · nowrolling trajectoryvs. leaguestabilized?
Hard-Hit % Allowed39.8%
39.8%*
lg avg 40.0% ▼−0.2%vs his norm —
123 / 50 BBE
Barrel % Allowed4.1%
4.1%*
lg avg 8.0% ▼−3.9%vs his norm —
123 / 60 BBE
xwOBA Allowed.317
.317*
lg avg .315 ▲+.002vs his norm —xwOBA Allowed is above the ~.315 league average — expect it to fall.
191 / 200 TBF
xERA4.19
4.19*
lg avg 4.10 ▲+0.09vs his norm —xERA is above the ~4.10 league average — expect it to fall.
191 / 200 TBF
ERA5.74
5.74*
lg avg 4.10 ▲+1.64vs his norm —ERA is above the ~4.10 league average — expect it to fall.
42.3 / 200 IP
Strikeout %23.0%
norm23.0%*
lg avg 22.0% ▲+1.0%vs his norm −2.3% ▼
191 / 70 TBF
Walk %11.5%
normbelievable since Jun 2911.5%*
lg avg 8.0% ▲+3.5%vs his norm +0.9% ▲
191 / 170 TBF
BABIP Against.339
.339*
lg avg .295 ▲+.044vs his norm —BABIP Against is above the ~.295 league average — expect it to fall.
123 / 800 BIP
Swinging-Strike %13.1%
13.1%*
lg avg 11.0% ▲+2.1%vs his norm —
191 / 60 TBF
Chase %32.0%
32.0%*
lg avg 28.5% ▲+3.5%vs his norm —
191 / 60 TBF
Fastball Velo97.4 mph
97.4 mph*
lg avg 94.0 mph ▲+3.4 mphvs his norm —
783 / 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% 23.0%→24.2%signal26 K — K% 23.0% (signal) lifted to career ~25.3% → projected 24.2% over ~23 remaining IP.
xERA 4.19noise3.73 ERA — xERA 4.19 (noise) blended 6% skill / 94% league 3.70 at 27 IP.
BB% 11.5% + contactsignal1.26 WHIP — a 12% walk rate plus BABIP-against 0.302 gives a 1.50 skill WHIP, blended 6…
run support + role1-1 W — wins ride run support and how deep he goes, not just skill.
role (closer)2-3 SV — role: closer.
rosterdeep6 SV, 3.73 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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