De Rossi, who has made over 500 appearances in 15 seasons with his Italian club, has previously been linked with a move to Man United, but is widely expected to end his career in Rome.
The experienced Italian has also revealed that Keane "is the only person in the world" that he has asked for a photo.
"Keane is my absolute hero. The 16 on my shirt is, along with the birthday of my daughter Gaia, dedicated to him," De Rossi told Roma's official website. "He is the only person in the world I asked for a photo with, two years ago. I was too embarrassed to ask Diego Maradona, but with Keane I couldn't resist."
Keane won seven Premier League titles with Man United, in addition to the Champions League in 1999.