MLB Daily DeltaWeek 25 · September 10, 2026
Engraved portrait of Stephen Kolek
week 25
this weekHOLD
last weekHOLD

Stephen Kolek

KC·P
data as of September 10, 2026·week 25
ON THE 60-DAY IL
Hold · leans buy skill near league average (3.84); strikeout rate 15% is stable and well below league, limits the ceiling; a hold that leans buy — skill sits a hair above league, worth watching.med 0.60
ROSK 8ERA 3.84WHIP 1.32W 1–2SV 0

Kolek is a hold — average skill, low strikeouts cap the ceiling.

His expected ERA is 3.84, about a quarter-run better than the league average of 4.10, and with 224 batters faced that number is stable. The problem is how he gets there: he strikes out 15.2% of batters against a league average of 22%, and that is not a small sample fluke — it is below his own 17% career baseline and has been stepping down. A pitcher who misses that few bats leans on contact management, and his is only slightly better than average: .303 expected wOBA allowed against .315, with hard-hit and barrel rates a touch under league. His walk rate of 5.4% is genuinely good and keeps him viable. The expected ERA has been improving, so there is no decline to sell into. There just is not enough swing-and-miss to push him past average. Hold. 8 K ROS makes him a deep-league streamer at best — average profile means hold, not a stash worth chasing.

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

  • xeraSIGNALskill near league average (3.84)
  • 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
.303*
lg avg .315 ▼−.012vs his norm —
224 / 200 TBF
xERA3.84
3.84*
lg avg 4.10 ▼−0.26vs 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%signal8 K — K% 15.2% (signal) lifted to career ~17.0% → projected 16.1% over ~12 remaining IP.
xERA 3.84signal3.84 ERA — regresses up toward xERA 3.84 (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 + role1-2 W — wins ride run support and how deep he goes, not just skill.
role (starter)0 SV — role: starter, not in the save mix.
rosterdeep8 K ROS, 3.84 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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