The 33-year-old has been a prolific goalscorer from midfield over the years and would not relish taking on a more defensive role.
"I have never been a defensive kind of player," he was quoted as saying on The Sun's website. "I love getting up and down the pitch and arriving late into the penalty area.
"If I felt I wasn't getting there, I wouldn't want to hang around too long.
"I'll be the first to know when I'm no longer capable of doing that job. Mind you, I'll probably have been sold before then!"