I used bases.chat, the baseball AI program created by fellow SABR member Ted Ingram, to create this list. The qualifiers for different time periods were used since this rule has changed a few times. See Rate Stats Qualifiers from mlb.com.
For Rogers Hornsby in 1921 there were 2 games left in the season. After 584 ABs & 664 PAs he had a .402 batting average. The Cardinals had no chance to make the post season. Yet he played the last 2 games of the season. He went 0 for 8 and his average fell below .400 to .397.
|
Player
|
Qualifier
|
Season
|
Final AVG
|
Peak AVG
|
Last Day at .400
|
|
Burkett
|
60% team G
|
1899
|
0.395
|
0.405
|
9/4/1899
|
|
McGraw
|
60% team G
|
1899
|
0.391
|
0.404
|
8/26/1899
|
|
Speaker
|
60% team G
|
1912
|
0.383
|
0.405
|
8/31/1912
|
|
Joe Jackson
|
60% team G
|
1913
|
0.373
|
0.409
|
8/4/1913
|
|
Ty Cobb
|
60% team G
|
1915
|
0.369
|
0.400
|
8/3/1915
|
|
Speaker
|
60% team G
|
1916
|
0.388
|
0.401
|
8/13/1916
|
|
Speaker
|
100 G
|
1920
|
0.388
|
0.421
|
8/16/1920
|
|
Heilmann
|
100 G
|
1921
|
0.394
|
0.419
|
9/24/1921
|
|
Hornsby
|
100 G
|
1921
|
0.397
|
0.415
|
10/1/1921
|
|
Ruth
|
100 G
|
1923
|
0.394
|
0.405
|
9/1/1923
|
|
Ruth
|
100 G
|
1924
|
0.378
|
0.408
|
8/16/1924
|
|
BaHerman
|
100 G
|
1929
|
0.383
|
0.414
|
9/1/1929
|
|
Klein
|
100 G
|
1930
|
0.385
|
0.407
|
8/16/1930
|
|
BaHerman
|
100 G
|
1930
|
0.393
|
0.405
|
8/18/1930
|
|
Vaughan
|
100 G
|
1935
|
0.385
|
0.407
|
9/10/1935
|
|
Medwick
|
100 G
|
1937
|
0.374
|
0.402
|
8/19/1937
|
|
DiMaggio
|
100 G
|
1939
|
0.381
|
0.409
|
9/10/1939
|