Non-uniform playing area: Fenway Park in the 1960 and 1962 BA races.

Pete Runnels played MLB 1951-1964.  His batting average (BA):

Washington .274 seven seasons
Boston .320 (led AL twice in five seasons)
Houston .246 two seasons
career .291

Suspicious, right?  Let's look at his home/road splits with Boston when he played his home games in Fenway Park:

1958: .365/.279 .322 second to teammate Ted Williams (.328)
1959: .335/.294 .314 third behind Tigers Kuenn (.353) and Kaline (.327)
1960: .338/.300 led AL with .320
1961: .326/.306 .317
1962: .332/.319 led AL with .326

In 1960 Runnels beat Al Smith of Chicago .320 to .315.  Smith's 1960 splits were: .321/.308.

In 1962 Runnels beat Mickey Mantle .326 to .321.  Mantle's 1962 splits were: .327/.316.

The differences home over road:
1960: Runnels 38, Smith 13
1962: Runnels 13, Mantle 11.

I had expected to find that Runnels had led in BA those two seasons because he played his home games in Fenway Park but his advantage, while significant, does not seem to be as aberrant as I had thought and his beating of Mantle was not impacted much.

However, Runnels beat Mantle, in part, by not playing his team's final games in 1962.  Yankee manager Ralph Houk tried to help Mantle lead the AL in BA by batting him first instead of fourth in the Yankee's final four games.  This may have been done both to help Mantle get enough plate appearances (PA) to qualify (Mantle had missed a month due to injury) and also to give him more opportunities to raise his BA.  Mantle finished with 502 PA, exactly enough.

In 1962 Boston played 160 games, two short of the maximum 162.  The final four games were played in Boston, so the Red Sox had control over whether those games were played if weather became an issue.

157 Tuesday, Sep 25 against Chicago
158 Wednesday, Sep 26 against Chicago - Runnels final game of season
159 Sunday, Sep 30 against Washington
160 Sunday, Sep 30 against Washington

It appears a game was not played against Washington on Saturday.  Boston played one fewer games against both Washington (in Washington) and Detroit in 1962.

Through Boston game 156 Runnels BA was .328.  Runnels did not play in game 157 when Boston faced tough lefty Juan Pizarro; Runnels was a lefty batter and was 1 for 6 (.167) against Pizarro in 1962.  Runnels went 0 for 4 in game 158 dropping his BA to .326.  Runnels did not play again in 1962.  See Runnels game log.

See Mantle's game log.

On Sept. 25 Mantle went 4 for 4 raising his BA from .312 to .320.  Runnels .328.

Sept. 26 Mantle went 2 for 4: .322.  Runnels .326.

With Mantle closing in, Runnels sat on his lead.  It worked.  By the time Boston played that season ending doubleheader on Sept. 30 Mantle had dropped to .318.  Still, Runnels sat.  Mantle finished 2 for 3 including his 30th home run, raising his BA to .321.  Runnels played it safe and led the AL in BA for the second time in three years.  Mantle won his third AL MVP award and the World Series.