Brentford manager Uwe Rosler has told potential suitors Karleigh Osborne is not up for sale.
Charlton made an enquiry about the the 23-year-old last week but Rosler insists he wants to keep Osborne at Griffin Park.
The Bees manager told the Hounslow Chronicle: "I want to work with four centre-halves next season so he's not available.
"We want to strengthen and build on what we have here in order to reach the next level.
"Charlton's valuation of Karleigh wasn't even close to what we were thinking, but we're not looking to sell him anyway."