MLB Daily DeltaWeek 27 · September 27, 2026
Portrait of Reynaldo López
Reynaldo López
ATL · P
Change to
Portrait of Riley O'Brien
Riley O'Brien
STL · P
Change to
Who's more valuable, rest of season

Too close to call.

They split your categories 1–1, 2 even. Take whoever fills a bigger need.

Head-to-head
K
◀
ERA
WHIP
▶
W
SV n/a

Reynaldo López wins 1 (ERA); Riley O'Brien wins 1 (WHIP); 2 even; SV n/a.

04

Under the hood

Underlying skill — each value vs league avg
Fastball Velolg 94.0 · higher = better
Reynaldo López
94.1
Riley O'Brien
97.7
Swinging-Strike %lg 11.0% · higher = better
Reynaldo López
10.2%
Riley O'Brien
11.9%
Strikeout %lg 22.0% · higher = better
Reynaldo López
21.1%
Riley O'Brien
23.2%
Chase %lg 28.5% · higher = better
Reynaldo López
27.2%
Riley O'Brien
29.2%
Hard-Hit % Allowedlg 40.0% · lower = better
Reynaldo López
35.9%
Riley O'Brien
42.2%
Barrel % Allowedlg 8.0% · lower = better
Reynaldo López
7.2%
Riley O'Brien
7.5%
xwOBA Allowedlg .315 · lower = better
Reynaldo López
.335
Riley O'Brien
.340
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
Reynaldo López
2.675.06
lg xERA 4.10
now 3.31
4.43
Riley O'Brien
2.675.06
lg xERA 4.10
now 3.20
4.53
WHIPlower is better
Reynaldo López
.9001.54
now 1.33
1.38
Riley O'Brien
.9001.54
now 0.99
1.36

Volume · rest of season
Strikeoutshigher is better
Reynaldo López
4043.40
now 31
0
Riley O'Brien
4043.40
now 27
0
Winshigher is better
Reynaldo López
.0004.20
now 2
0–0
Riley O'Brien
.0004.20
now 3
0–0

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

If you already own them — trade angle
SellReynaldo López — sell.conf 0.77
SellRiley O'Brien — sell.conf 0.81
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