I think it's definitely in play, but mostly because I don't see the Sixers as all that much better than us. Essentially, the Sixers and Celtics are very similar to me, as they're a great defensive team that lacks a standout offensive threat. Without a premier talent that can light up the scoreboard, teams like these two are in that non-favorite range where they're simply not likely to win a title.
However, for both teams I feel that winning the division is crucial to going far in the playoffs. If the Celtics were to get the 3 seed, they'd be able to have a real shot at winning the first round, and maybe get lucky and only have to play one elite team in the East. If Indiana could get past the Heat or Bulls, and the Celtics held the 3 seed, they could get lucky and only have to make it through one of Chicago or Miami. If that were to happen, it'd still be unlikely that Boston could win a title, but not impossible. In a season like this, it's definitely worth it to try and win some games and hope for some luck.