Hodgson said Ferdinand had taken his omission in a "gracious" manner.
"He was obviously disappointed. I'd be surprised had he not been," Hodgson said.
"He was very gracious and he wished myself and the team the very best of luck in the tournament."
He stressed he had no doubts over Ferdinand's ability to get through a tournament on a physical basis.
"I had a private conversation with Sir Alex (Ferguson) 10 days ago," Hodgson said. "I think Rio has done exceptionally well this year. He's played a lot of matches through injury.
"He's got himself on the field of play when many a player wouldn't have done so.
"I'm also wary of that because I know there have been times in the season where Rio has played three matches in a week. I would be lying if that [the ability to play matches close together] was the major reason for not selecting him.
"It was purely on other footballing reasons. I admire Rio Ferdinand as a player.
"I think he's a fine footballer and I respect him, but I had to pick a squad with defenders I wanted to take to the Euros."
Hodgson said Ferdinand's lack of recent international action had been a major factor.
"One game in the last year and only three games since 2010," Hodgson said.
"Having taken over the squad, I've been very conscious of the fact I'm to some extent being parachuted in to take charge of a Capello squad which has qualified for this tournament.
"I wanted to, at least where I can, remain faithful to the players who got us there."