I can add additional info from the ATP site
"Last season, I told everyone from my family and my brother, 'I will push myself,'" said the 31 year old. "I want to again. I want to try [this] season to play again and practise concentration, try to do [what] I can, because I'm already not so young. Maybe I have two more years, maybe one more year."
sooo he is serious about it !