This was a rumor coming from the Philly Flyers' own sources BS21 -- not even from Boston's.
Thomas is one of the better "available" goaltenders in therms of SV% and GAA this year, only RFA Jaroslav Halak is clearly better, and you know Halak will cost more talent.
The contract in raw dollar terms is roughly appropriate for a player of his skill (equal or superior statistical goaltenders tend to get paid a bit more, actually). It isn't inconceivable that someone might send us an equally expensive veteran back who would fill a hole for us (read: Gagne) if Thomas represents a sufficiently significant upgrade (which in Philly, he would).
Philly is also one of the teams Thomas could realistically consider suspending his NMC to go to, since they're playoff contenders.