The former Manchester United boss gave his opinion on Gerrard in his autobiography.
"I think everyone who's seen the comments will think they are harsh," Rodgers told talkSPORT.
"I've watched Gerrard for many years and recognised he's a top player, but it's only when you come in and work with the man that you realise how professional he is on a daily basis.
"His performance level at 33 years of age shows he's a top, top player. He's a great talent, a wonderful player and I don't think anyone could argue against that."
QPR midfielder Joey Barton also defended Gerrard, saying the England captain was a better player than Ferguson's long-time skipper Roy Keane.
Barton said on Twitter: "On a serious note. Gerrard for me, was better than Roy Keane. At one stage he was up there with the best midfielders in the World.
"Lucky enough to have Played against them both on number of occasions. Steven Gerrard streets ahead IMO. Keane was v good but SG better...
"People forgetting Keane played with the best in the World at United. He wasn't same player with the Republic. Was he?"