MLB Daily DeltaWeek 17 · July 18, 2026
Engraved portrait of Stephen Kolek
week 17
this weekBUY
last weekHOLD

Stephen Kolek

KC·P
data as of July 18, 2026·week 17
flipped from HOLD on July 18, 2026
Buy stable xERA 3.79, 0.31 below league, production is earned; velocity stable and above league; strikeout rate 15% is stable and well below league, limits the ceiling; add now.med 0.69
ROSK 34ERA 3.79WHIP 1.32W 3–7SV 0

Kolek is a buy — his xERA and velocity signal real growth.

His expected ERA is 3.79, which is 0.31 below league average, and he has faced enough batters for that number to be reliable. The metric has stepped down across the sample, showing his run-prevention skill is improving. His fastball velocity has ticked up to 94.2 mph, above his baseline, and the trajectory is still rising. He limits hard contact (36.9% hard-hit allowed vs. 40.0% league) and barrels (6.8% vs. 8.0%). His walk rate is well below league, and his chase rate is also better than average. The one caveat: his strikeout rate is a low 15.2%, which caps his ceiling, but it is stable and he compensates with weak contact and control. The surface is earned, and the underlying numbers point to a pitcher who is growing into his stuff. Buy. 34 K and 3.79 ERA make him a deep-league add with a safe floor, not a flashy one.

VS His Norm

  • Strikeout %15.2%—−1.8% ▼vs his ~17.0% career norm
  • Walk %5.4%—−0.8% ▼vs his ~6.2% career norm

Drivers

  • xeraSIGNALstable xERA 3.79, 0.31 below league — production is earned
  • p_fastball_veloSIGNALvelocity stable and above league
  • p_k_pctSIGNALstrikeout rate 15% is stable and well below league — limits the ceiling
metric · nowrolling trajectoryvs. leaguestabilized?
Hard-Hit % Allowed36.9%
36.9%*
lg avg 40.0% ▼−3.1%vs his norm —
176 / 50 BBE
Barrel % Allowed6.8%
6.8%*
lg avg 8.0% ▼−1.2%vs his norm —
176 / 60 BBE
xwOBA Allowed.303
believable since Jun 22.303*
lg avg .315 ▼−.012vs his norm —
224 / 200 TBF
xERA3.79
3.79*
lg avg 4.10 ▼−0.31vs his norm —
224 / 200 TBF
ERA4.50
4.50*
lg avg 4.10 ▲+0.40vs his norm —ERA is above the ~4.10 league average — expect it to fall.
54 / 200 IP
Strikeout %15.2%
norm15.2%*
lg avg 22.0% ▼−6.8%vs his norm −1.8% ▼
224 / 70 TBF
Walk %5.4%
norm5.4%*
lg avg 8.0% ▼−2.6%vs his norm −0.8% ▼
224 / 170 TBF
BABIP Against.280
.280*
lg avg .295 ▼−.015vs his norm —BABIP Against is below the ~.295 league average — expect it to rise.
176 / 800 BIP
Swinging-Strike %9.6%
9.6%*
lg avg 11.0% ▼−1.4%vs his norm —
224 / 60 TBF
Chase %26.7%
26.7%*
lg avg 28.5% ▼−1.8%vs his norm —
224 / 60 TBF
Fastball Velo94.2 mph
94.2 mph*
lg avg 94.0 mph ▲+0.2 mphvs his norm —
837 / 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% 15.2%→16.1%signal34 K — K% 15.2% (signal) lifted to career ~17.0% → projected 16.1% over ~53 remaining IP.
xERA 3.79signal3.79 ERA — regresses up toward xERA 3.79 (signal): elite skill, but overperforming even…
BB% 5.4% + contactsignal1.32 WHIP — a 5% walk rate plus BABIP-against 0.292 gives a 1.33 skill WHIP, blended 65…
run support + role3-7 W — wins ride run support and how deep he goes, not just skill.
role (starter)0 SV — role: starter, not in the save mix.
rosterdeep34 K ROS, 3.79 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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