MLB Daily DeltaWeek 19 · August 4, 2026
Portrait of David Peterson
David Peterson
CHC · P
Change to
Portrait of Mitch Keller
Mitch Keller
PIT · P
Change to
Who's more valuable, rest of season

Too close to call.

They split your categories 22. Take whoever fills a bigger need.

Head-to-head
K
ERA
WHIP
W
SV n/a

David Peterson wins 2 (K, ERA); Mitch Keller wins 2 (WHIP, W); SV n/a.

04

Under the hood

Underlying skill — each value vs league avg
Fastball Velolg 94.0 · higher = better
David Peterson
92.3
Mitch Keller
93.3
Swinging-Strike %lg 11.0% · higher = better
David Peterson
9.9%
Mitch Keller
9.7%
Strikeout %lg 22.0% · higher = better
David Peterson
18.8%
Mitch Keller
17.7%
Chase %lg 28.5% · higher = better
David Peterson
29.3%
Mitch Keller
29.4%
Hard-Hit % Allowedlg 40.0% · lower = better
David Peterson
42.5%
Mitch Keller
42.3%
Barrel % Allowedlg 8.0% · lower = better
David Peterson
7.1%
Mitch Keller
7.4%
xwOBA Allowedlg .315 · lower = better
David Peterson
.343
Mitch Keller
.355
stabilized — trust it · small sample yet · dashed = league avg · right = better
05

The tape

Rest-of-season projection · bold = leads
rest-of-season projection current season projection range
Rate · earned-run quality
ERAlower is better
David Peterson
4.025.51
lg xERA 4.10
now 5.18
4.70
Mitch Keller
4.025.51
lg xERA 4.10
now 4.35
4.97
WHIPlower is better
David Peterson
11.76
now 1.59
1.41
Mitch Keller
11.76
now 1.17
1.38

Volume · rest of season
Strikeoutshigher is better
David Peterson
4064.80
now 56
41
Mitch Keller
4064.80
now 51
34
Winshigher is better
David Peterson
.0006.60
now 3
13
Mitch Keller
.0006.60
now 5
24

SV — not applicable. Both pitch out of the rotation.

If you already own them — trade angle
SellDavid Peterson — sell.conf 0.83
SellMitch Keller — sell.conf 0.90
Tweet