Sky Sports News understand that Charlton have made a bid for Watford's Jay DeMerit.
It is understood The Addicks have offered their Championship rivals £300,000 for the America international.
Watford are known to have financial issues and could be forced to cash-in on DeMerit, who has been with the club for four-and-a-half years, playing nearly 150 games for The Hornets.
Charlton are currently bottom of the Championship, some nine points adrift of safety and boss Phil Parkinson is desperately looking to bolster his options.
One deal Parkinson has managed to finalise is the extension of Graeme Murty's loan from Reading.
Meanwhile, Charlton have confirmed that Martin Christensen has left the club on loan.
The Danish Under-21 international has joined Lyngby in his homeland.