Although the idea of Boston being a 3rd team in a Asik-to-Philly deal is plausible... that's not what the rumor is really suggesting. Mark Stein just says that Boston is another possible destination for Asik... meaning that it's not a guarantee the Rockets will trade with Philly.
Philly's blog is then just trying to connect the dots and suggesting that the 3rd team rumored in their Asik-to-Philly deal might be Boston.
That said, why would Philly want Asik at all? They are tanking. Asik is a 5th wheel of a team already contending.