Sox-Yankees: 5 things to know

With the Red Sox and Yankees in the midst of a suddenly intriguing September series (tonight at 7 on ESPN), here are five things to know:

1. Losing their grip: The Yankees had a 10-game division lead after the games of July 18 (led Orioles by 10 and Rays by 10½). They are now tied with the Orioles and just 2 games ahead of the Rays. Since July 19, the Yankees have gone 22-28, the Rays 30-19 and the Orioles 32-18.

2. Can they hang on? According to Elias, only twice during the Divisional Era (since 1969) have the Yankees failed to win the AL East after leading the division outright at any time in September. In 2010, the Yankees finished second but made the playoffs. In 1974, they finished second and missed the playoffs that year.

3. Don't blow it: According to Elias, the Yankees have never blown a division/league lead of more than 6 games. The largest blown lead was 6 games in 1933.

4. Unfriendly Fenway: The Red Sox are 33-41 at Fenway Park this season. According to Elias, Boston has lost as many as 42 home games only two other times in the past 30 seasons -- 1983 (38-43) and 1997 (39-42). If the Red Sox lose the next two games, they would be 10 games under .500 at home for the first time at any point in any season since they finished 34-47 in 1965.

5. Going long: The Yankees have hit 31 home runs against the Red Sox this season, 4 shy of the record set in 1961. They have five games left vs. Boston this season.