The 36-year-old says former Roma director Walter Sabatini sold him behind his back.
"I never wanted to quit AS Roma but other people decided for me. The sporting director Walter Sabatini decided to sell me, he already had an agreement with Watford before I knew anything about it. Can you believe that?" Holebas told the Watford Observer.
"I asked Sabatini: 'Why?'
"Then after a few days I said: 'Let's stop discussing man and find a solution now'
"And yes it took me a long time to accept Watford. And in the end I only accepted because it was the Premier League. I also saw which players they were signing back then and thought to myself: 'Ok, this could become interesting after all'.
"But I wanted to stay there. My time at Roma was too short. It was only a year but what an amazing year it was and very successful from a personal point of view. Besides, Rome was such an awesome city and there I played with great players like De Rossi, Ashley Cole and Nainggolan. And a legend like Totti.
"If he is more important than the Coliseum? Not sure about that but he is huge in Rome. He dedicated his whole career to Roma and never left the club. He always helped everyone, including me. Francesco is such a positive person. And the goal against Inter Milan was one of the best of my career also because it was against a massive club like Inter Milan."