Division title carries weight
The Yankees need home field advantage in the playoffs because they (or the winner of the AL pennant) will not have it for the World Series. Recall, the league winning the All-Star Game earns home field.
There is also a lot of money at stake in advancing to and winning the World Series. Each member of the 2009 Yankees earned $365,052.73. The losing Philles received about $100,000 less.
Compare that to the 1903 Boston Americans, the first team to win the World Series. Each player got $1,182.00.
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