The 34-year-old insists his long-term goal is to force his way back into Harry Redknapp's plans at Pompey, with whom he signed a new one-year deal in the summer.
His agent John Mac told The News: "Linvoy needs to get some games, so is looking to go to Charlton.
"He needs to get fit first and then we will sort something.
"The fact is he needs to play football and get 10 to 15 games under his belt.
"He still has a future at Pompey, though. This isn't the end for him.
"He played games in pre-season and is a part of things still."