Zheng Zhi has turned down the offer of a new contract at Charlton and will now look for a new club.
The Chinese midfielder moved to The Valley on loan at the start of 2007 but his arrival could not stop the Addicks from being relegated to the Championship.
He secured a permanent switch that summer and has continued to impress over the past two years.
However, Zheng's deal expired at the end of June and he has decided not to stay after Charlton dropped down to League One.
Manager Phil Parkinson told the club's official website: "We have spoken to ZiZi's advisors about a new deal, but they've made clear that he's not keen on playing in the third flight.
"He wants to play at the highest possible level and it's clear they are pursuing other options."
Jonathan Fortune and Darren Randolph are also out of contract but are continuing to train with the club while their futures are sorted, while Matt Holland has linked up with Colchester for pre-season.
"Unfortunately, we have been unable to finalise concrete contract offers with the remaining players, but we certainly haven't ruled anything out at the moment," added Parkinson.
"Jonathan and Darren are still training with the club, while Matty has decided to do his pre-season at Colchester United because it's closer to his home."