Out-of-contract Charlton defender Kelly Youga is set to link up with the Addicks for pre-season training.
The left-back missed the entire season with a long-term knee injury but will be offered the chance to prove his fitness and possibly earn a new deal.
"Kelly has been out for 20 months or so, which is a long time," said manager Chris Powell.
"He's also out of contract this summer, but he's nearing fitness again and he's indicated that he's keen to return in July and start pre-season training with us.
"He needs to work on his fitness and play some games and we can't really talk about contracts until we have monitored his progress, but training with us in pre-season suits both parties."
Christian Dailly, Jose Semedo, Therry Racon, Kyel Reid, Joe Anyinsah, Miguel Llera and Jonathan Fortune will also be out of contract at the end of June, and no decisions have been made on their future yet.