MLB Daily DeltaWeek 25 · September 10, 2026
Portrait of George Kirby
George Kirby
SEA · P
Change to
Portrait of Spencer Arrighetti
Spencer Arrighetti
TOR · 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

George Kirby wins 2 (ERA, WHIP); Spencer Arrighetti wins 2 (K, W); SV n/a.

04

Under the hood

Underlying skill — each value vs league avg
Fastball Velolg 94.0 · higher = better
George Kirby
96.7
Spencer Arrighetti
92.4
Swinging-Strike %lg 11.0% · higher = better
George Kirby
11.4%
Spencer Arrighetti
10.7%
Strikeout %lg 22.0% · higher = better
George Kirby
19.9%
Spencer Arrighetti
21.8%
Chase %lg 28.5% · higher = better
George Kirby
34.8%
Spencer Arrighetti
26.5%
Hard-Hit % Allowedlg 40.0% · lower = better
George Kirby
40.3%
Spencer Arrighetti
30.8%
Barrel % Allowedlg 8.0% · lower = better
George Kirby
6.9%
Spencer Arrighetti
9.1%
xwOBA Allowedlg .315 · lower = better
George Kirby
.310
Spencer Arrighetti
.350
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
George Kirby
26.28
lg xERA 4.10
now 3.77
4.03
Spencer Arrighetti
26.28
lg xERA 4.10
now 1.34
4.87
WHIPlower is better
George Kirby
1.011.54
now 1.22
1.35
Spencer Arrighetti
1.011.54
now 1.13
1.42

Volume · rest of season
Strikeoutshigher is better
George Kirby
4078.20
now 59
11
Spencer Arrighetti
4078.20
now 43
12
Winshigher is better
George Kirby
.0009.40
now 5
11
Spencer Arrighetti
.0009.40
now 7
13

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

If you already own them — trade angle
Hold · steadyGeorge Kirby — hold.conf 0.60
SellSpencer Arrighetti — sell.conf 0.90
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