George Leclair has allowed the most earned runs in a game, with 20 earned runs versus the Indianapolis Hoosiers on August 16, 1914.

most er by a pitcher in a game
Interpreted as:
most er by a pitcher in a regular-season game
8/16/1914 Leclair 9/28/1923 Ehmke 9/15/1901 Bracken 8/26/1938 Feller 6/9/1936 Castleman 8/4/1933 Rhem 9/11/1927 McQuillan 6/20/1925 Greene 9/5/1919 Noyes 9/12/1902 Katoll 8/20/1902 Hughes 9/5/1901 Maul 7/24/1901 Patten 5/16/2011 Mazzaro 8/3/1998 Oquist 8/14/1977 Travers 6/28/1947 Jurisich 4/16/1942 McCrabb 9/28/1940 Dean 6/8/1940 Doyle 7/25/1937 Walkup 9/11/1936 Lisenbee 7/11/1931 Schesler 7/25/1929 Miljus 7/21/1924 Lyons 9/24/1901 Phillips 6/24/1901 Miller 0 2 4 6 8 10 12 14 16 18 20 20 16 16 15 15 15 15 15 15 15 15 15 15 14 14 14 14 14 14 14 14 14 14 14 14 14 14
NAME DATE TM OPP DEC ER GS CG GF SHO SV IP H TBF R HR BB IBB HBP SO WP
George Leclair illustration George Leclair
8/16/1914 PTF @ IND L 20 1 1 0 0 0 8.0 24 51 21 0 8 0 0 0
Howard Ehmke illustration Howard Ehmke
9/28/1923
BSA logo BSA
vs
NYY logo NYY
L 16 1 0 0 0 0 6.0 21 42 17 2 4 0 6 0
Jack Bracken illustration Jack Bracken
9/15/1901
CLE logo CLE
@
DET logo DET
L 16 1 1 0 0 0 7.0 24 49 21 1 3 2 1 1
Bob Feller illustration Bob Feller
8/26/1938
CLE logo CLE
@
NYY logo NYY
L 15 1 0 0 0 0 7.0 15 44 15 2 9 0 7 1
Slick Castleman illustration Slick Castleman
6/9/1936
NYG logo NYG
@
CIN logo CIN
L 15 1 1 0 0 0 8.0 18 45 15 1 3 0 2 1
Flint Rhem illustration Flint Rhem
8/4/1933
PHN logo PHN
vs
NYG logo NYG
L 15 1 0 0 0 0 8.0 21 47 16 0 3 1 1 0
Hugh McQuillan illustration Hugh McQuillan
9/11/1927
BSN logo BSN
@
CIN logo CIN
L 15 1 0 0 0 0 6.2 17 39 16 1 3 0 2 0
Nelson Greene illustration Nelson Greene
6/20/1925
BKN logo BKN
@
PIT logo PIT
15 0 0 1 0 0 6.2 18 40 15 3 3 0 0 1
Win Noyes illustration Win Noyes
9/5/1919
PHA logo PHA
vs
BSA logo BSA
L 15 1 0 0 0 0 7.0 22 43 15 1 2 1 3 0
Jack Katoll illustration Jack Katoll
9/12/1902
BAL logo BAL
vs
WSH logo WSH
L 15 1 1 0 0 0 9.0 23 49 15 0 1 0 0 0
Jim Hughes illustration Jim Hughes
8/20/1902
BKN logo BKN
@
CIN logo CIN
L 15 1 1 0 0 0 8.0 21 45 15 1 3 0 3 0
Al Maul illustration Al Maul
9/5/1901
NYG logo NYG
vs
PIT logo PIT
L 15 1 1 0 0 0 9.0 22 52 15 1 5 0 3 0
Casey Patten illustration Casey Patten
7/24/1901
WSH logo WSH
@
CWS logo CWS
L 15 1 1 0 0 0 8.0 20 52 17 0 4 0 1 0
Vin Mazzaro illustration Vin Mazzaro
5/16/2011
KCR logo KCR
vs
CLE logo CLE
14 0 0 0 0 0 2.1 11 21 14 1 3 0 0 2 1
Mike Oquist illustration Mike Oquist
8/3/1998
OAK logo OAK
vs
NYY logo NYY
L 14 1 0 0 0 0 5.0 16 32 14 4 3 0 0 3 0
Bill Travers illustration Bill Travers
8/14/1977
MIL logo MIL
@
CLE logo CLE
L 14 1 0 0 0 0 7.2 18 45 14 2 4 0 1 4 2
Al Jurisich illustration Al Jurisich
6/28/1947
PHN logo PHN
@
NYG logo NYG
L 14 1 1 0 0 0 8.0 16 46 14 3 6 0 1 0
Les McCrabb illustration Les McCrabb
4/16/1942
PHA logo PHA
@
BSA logo BSA
14 0 0 1 0 0 4.0 14 29 14 2 2 1 0 1
Chubby Dean illustration Chubby Dean
9/28/1940
PHA logo PHA
@
BSA logo BSA
L 14 1 1 0 0 0 8.0 19 47 16 1 5 0 1 2
Carl Doyle illustration Carl Doyle
6/8/1940
BKN logo BKN
@
CIN logo CIN
14 0 0 0 0 0 4.0 16 36 14 1 4 4 2 2
Jim Walkup illustration Jim Walkup
7/25/1937
SLA logo SLA
vs
WSH logo WSH
L 14 1 0 0 0 0 8.0 16 44 14 1 5 0 3 1
Hod Lisenbee illustration Hod Lisenbee
9/11/1936
PHA logo PHA
@
CWS logo CWS
L 14 1 1 0 0 0 8.0 26 51 17 2 4 0 1 1
Dutch Schesler illustration Dutch Schesler
7/11/1931
PHN logo PHN
vs
NYG logo NYG
14 0 0 1 0 0 8.0 22 48 16 4 0 1 1 0
Johnny Miljus illustration Johnny Miljus
7/25/1929
CLE logo CLE
@
PHA logo PHA
L 14 1 0 0 0 0 3.0 13 25 14 3 3 0 0 0
Ted Lyons illustration Ted Lyons
7/21/1924
CWS logo CWS
@
WSH logo WSH
L 14 1 1 0 0 0 8.0 18 48 16 0 5 0 3 0
Results may be incomplete. StatMuse has complete game-level data for earned runs going back to the 1923 season.
Some of the information used here was obtained free of charge from Retrosheet.

Explore