The 30-year-old’s current contract is set to expire at the end of the season and he has recently been linked with a move to Queens Park Rangers.
Johnson has struggled with injuries since joining the Cottagers.
“Andy Johnson is doing very well at the moment and that’s why the club are in talks with him to extend his contract by a year,” confirmed Jol.
“I expect him to sign it over the next month.
“He is already back to level I remember him being when I was Spurs manager. He’s scoring goals, he’s getting on the end of things, he’s very good at receiving the ball right now.
“He did interest me when I was at Tottenham, but he was too expensive then.”
