Aquilani has joined AC Milan on-loan for the season.
Asked why Aquilani was allowed to go after impressing in pre-season, Comolli said: "With him it was more a question of opportunities to play. He's obviously a big player, he's got a very good resume and he's a very good player. But Kenny and the coaching staff felt he would play in a certain position.
"As I told Alberto during the summer, unfortunately in that position is someone called Steven Gerrard and it would have been difficult for Alberto to play."