Better and worse news for the Boston Red Sox (though they might have caught a break with their rainout earlier this evening). We went back to BB-Ref and looked at 2-9 records from two perspectives:
--Records of teams since 1901 who have begun the year 2-9;
It turns out that 72 teams have started the year 2-9 since 1901. Of those teams, six would be playoff teams, and three would win the World Series: the 1914 Boston Braves, the 1935 Detroit Tigers, and the 1991 Minnesota Twins.
On average, however, teams that started 2-9 played ever so slightly worse over the course of the season than the teams that started 0-5 (69-87 as opposed to 69-86).
Time didn't permit a look at the full "Year -1," "Year 0" and "Year +1" results.
As for the 2010 results, there were a total of 132 distinct streaks of 2-9 play last year. Most of these are repetitive sequences for teams that finished poorly in the standings. The full distribution of these 2-9 streaks in 2010 can be seen in the chart at the right; three playoff teams, all from the NL, including the 2010 World Series champion San Francisco Giants, managed to have 2-9 streaks during the season. As the full distribution shows, however, 2-9 streaks are much more frequent for sub-.500 teams (about three times as frequent, at least in the 2010 sample.)
So one measure of the Red Sox' chances to make the post-season can be made based on the fact that three of the eight 2010 playoff teams had a 2-9 streak last year. That means that their playoff chances are currently 37.5%.