I don't know the exact date of the surgery but he tore his second ACL in the 5th week of 2015 season. Then he sat out 2015. He had ACL surgery but came back too soon and had to have a touch up surgery to trim the meniscus in 2016, which caused him to miss most of the 2016 season. However now the doctors have reviewed his knee and it has healed nicely and he just needs to strengthen the muscles to stabilize the joint.  He will be 100% by training camp. 

Obviously, I think Charles can be a great contributor to the team in 2017 but I am also realistic and realize that he isn't a long term solution. But for now, he is still a real talent.