Trading doesn't work that way. You can't trade a guy who is injured. The other guy would be stuck sitting him for over a month. In a 16 team league, I seriously doubt you have waiver wire options. Only if Robinson, Davis, D. Brown or Bradshaw were there would I drop Gerhart.
Matt ryan Bobby Rainey Terrance West Kendall Wright Randall Cobb DeAndre Hopkins Carpenter k Ravens BENCH J charles J Gordan A Robinson N Paul
James Jones or Julio Jones? It is a big difference. If it is James don't even consider it. Plus Charles was seen in warm ups so who knows when he plays. It even said he is slightly less than 50/50 to suit up. Is that khriy robinson? If so he could carry you through a 4 week injury to Charles bc Ingram will be out a month. Robinson isn't on the same level as Charles by any means but will be a stop gap. Your other issue is that your RB are injury based value with possible competition when the starter get back but you will even then likely see RB. Tate will be back week 5 after the bye week 4 a downgrade to West. Martin Will be back at some point and even if Rainey stays number 1 Martin will still be taking carries.
I wouldn't do it. Charles is the anchor of your team. You get rid of him, you're stuck with only rainey and west. and rainey did nothing against a bad falcons rushing defense to quell rumors he will take the starting job.