If this offer want sent to me I would hit decline without thinking twice.
Juan Pierre will not post similar numbers to Crawford. Crawford is one of the top 20 players in the game and should be BOUGHT right now, NOT sold.
Jordan Walden might not total as many saves as Broxton, but Jonathan Broxton worries me. This coming from a guy who stashed him away in his minor league system for two years in a Dynasty League knowing he would be filthy as a set up man/closer, he is not the same guy he was the first half of 2010 and all of 2008/2009. His heater sits in the low 90's instead of flirting with triple digits like it used to.
Jordan Walden is unproven and may not save as many games as Broxton, but he knows how to strike people out and the extra ~10 saves Broxton might contribute this season is not worth downgrading from a top 5 overall pick to Juan Pierre. It just doesn't make sense.
DO NOT sell Carl Crawford right now. You will NOT get close to fair value for him, and this guy is just banking on you being upset with his slow start. There's a reason you don't shuffle your roster after the first 10 games of the season. Guys like Pujols, Youkilis, Crawford, Hanley, etc. are off to very slow starts. DO NOT TRADE THEM.