The situation has a lot of hidden possibilites involved.
First of all, Recchi is to be traded because he does have value. There have been at least six teams who have shown interest in trading for Recchi according to today's Post-Gazette, and rumors abound suggest that Recchi is the hot player on the block, meaning his value will go nowhere but up as teams bid for him. The return he brings could be huge.
Secondly, Recchi adds nothing to this team. Why do they need him? They can lose without him just as easily as with him. He's not helping them win any games because, well, they don't win any games. So why not trade him and get what you can?
Lastly, here is where the the hidden possibilities surface. Recchi has a team and player option on his contract for next season. The team option is relatively high, while the player option is very low. Chances are, Recchi becomes a free agent over the summer and return to Pittsburgh. But those options alone make him more valuable. In most cases, teamsa re trading for impending unrestricted free agents, or rental players. Generally, they won't give up nearly as much for a rental as they would for a keeper. However, sometimes teams only want a rental and are willing to give up what it takes. Recchi is kind of the best of both worlds. If he fits in with his new team, he can be retained. If he doesn't fit in, he can walk. This could make him very attractive to potential trade partners.
And, just as a side note, the Therrien has said that there will be no captain this year. He said he wants to keep three alternates for the balance of the season and will then appoint a new captain next season. This is Crosby's team, not Recchi's. To deny Crosby the captaincy because he is only 19, despite the fact that he is the leader, is simply dumb. It's also ageism, saying he isn't as "good" as a veteran. And to add, Recchi doesn't provide any grit and the fact that he provides leadership is also in question.
If he's traded, the team likely will be worse this season, but does it really matter? Where they really destined to win THAT many more games even with Recchi? At least they could get a few players to help next season and beyond.