He's obviously not having a good season and it's highly doubtful that he is impressing anybody scouting him with his play.
Nonetheless at this time of year teams are always looking for players that can stay in the lineup in the playoffs (Frederic is at least that, right? right?) and provide a little sandpaper and maybe chip in the odd goal. Imagine NJ having to sit out MacDermid, they'll want somebody with some edge when they're up against Washington (Wilson). Or Edmonton needing to face Minny. Etc.
I mean, even the likes of Maroon get traded at the deadline. Despite it being a down year for Frederic, there will probably still be a couple buyers considering him, even if they have to wait a week or two for him if he has to shake off an injury. The Bruins will need to have the attitude that getting anything for him is better than letting him walk in July for nothing. I don't think you're getting more than a 2nd or 3rd round pick for him unless it is an expanded deal.