MLB Daily DeltaWeek 17 · July 22, 2026
Isaac Mattson
PIT · P
Change to
Zack Kelly
BOS · P
Change to
Who's more valuable, rest of season

Zack Kelly.

He projects to help you in more roto categories the rest of the way — strikeouts.

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

Zack Kelly wins 1 categories (K); Isaac Mattson wins 0 (none); 3 even; SV n/a.

04

Under the hood

Underlying skill — each value vs league avg
Fastball Velolg 94.0 · higher = better
Isaac Mattson
94.1
Zack Kelly
96.1
Swinging-Strike %lg 11.0% · higher = better
Isaac Mattson
10.7%
Zack Kelly
9.2%
Strikeout %lg 22.0% · higher = better
Isaac Mattson
20.6%
Zack Kelly
19.7%
Chase %lg 28.5% · higher = better
Isaac Mattson
26.7%
Zack Kelly
28.0%
Hard-Hit % Allowedlg 40.0% · lower = better
Isaac Mattson
46.4%
Zack Kelly
38.8%
Barrel % Allowedlg 8.0% · lower = better
Isaac Mattson
12.4%
Zack Kelly
8.2%
xwOBA Allowedlg .315 · lower = better
Isaac Mattson
.362
Zack Kelly
.368
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
Isaac Mattson
2.994.44
lg xERA 4.10
now 4.12
3.70
Zack Kelly
2.994.44
lg xERA 4.10
now 3.31
3.70
WHIPlower is better
Isaac Mattson
1.151.56
now 1.47
1.24
Zack Kelly
1.151.56
now 1.29
1.24

Volume · rest of season
Strikeoutshigher is better
Isaac Mattson
4022.60
now 15
15
Zack Kelly
4022.60
now 14
17
Winshigher is better
Isaac Mattson
.000.480
now 0
00
Zack Kelly
.000.480
now 0
00

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

If you already own them — trade angle
Hold · wait & seeIsaac Mattson — hold.conf 0.50
Hold · wait & seeZack Kelly — hold.conf 0.50
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