Wikipedia is listing Northern Ireland international Sammy Clingan as having already joined Charlton. He made his reputation at Nottingham Forest, but is a free agent after leaving Coventry in the summer.
Coventry fans were far from happy with him and were glad to see the back of their skipper: Clingan . It may be, however, that things didn't simply work out at the Ricoh for the midfielder, given the generally unhappy state of affairs there.
I can't find any independent corroboration of this story, but it is plausible in the sense that he would be a low cost way of strengthening the midfield. However, someone altered Chris Solly's entry on transfer deadline day to put him at West Ham.
The situation has now been clarified by Richard 'Creepy' Crawley of Pravda who has tweeted that Chris Powell has said that Clingan is welcome to train at Sparrows Lane if he wants, but it is not certain that he will want to.