Capello, who also confirmed Wayne Rooney's fitness, said: "I spoke with Steven on Sunday evening and explained why Rio will be captain against Montenegro. He understood everything - he knows the rules.
"I decided when I started as England manager who will be the captain and the vice-captain.
"When I spoke with Steven I told him, 'you were a fantastic captain and you have to play like a captain on Tuesday'."
Capello is confident Ferdinand's knee problems are behind him, adding: "I have monitored him - he is fit completely. Also I watched the game against Valencia. I think now he's 100% fit.
"He's really important for the other players, he speaks a lot during the game. It's really important for me, I prefer this kind of player on the pitch."
Ferdinand was named as Fabio Capello's skipper for the World Cup after Terry was sacked following allegations about his private life.
Capello explains why Rio is his captain
But the 31-year-old has only been able to fulfil his duties for two of the 10 England internationals since his appointment because of various injury problems. Tuesday marks his first competitive international appearance for 12 months.
He missed every match in South Africa with knee ligament damage sustained during England's first World Cup training session, and has been unavailable for 16 of England's last 22 games in all.
For Manchester United this season he has managed four appearances, while in 2009-2010 he turned out 21 times for his club.
Midfielder Gerrard led the side to victories in England's opening two fixtures of the Euro 2012 qualifying campaign.
But the Italian has reverted to his original appointment with Ferdinand leading out the side for the first time since the friendly international with Japan in Graz in late May.
Ferdinand said: "I didn't know if I was going to be captain or not. I was more concerned about being in the squad and being fit.
"The manager is always analysing you physically and mentally and you've got to perform. He has seen me as the right person and I'm delighted with that.
Missing the World Cup had been tough to endure, he added.
Young seeks starting spot
"The first 48 hours when I got the injury were the worst in terms of thinking of the consequences and analysing it.
"Missing the World Cup was a disaster for me but you've got to wipe yourself down and get on with it."
Ferdinand continued: "There are a few fresh faces - it's nice to train alongside Jack Wilshere and Adam Johnson, young hungry boys who are talented and trying to get in the team.
"It makes you feel a bit older but it's a good ambience and long may it continue."
Montenegro are unbeaten in three qualifiers, lending a huge amount of importance to Tuesday's match.
Ferdinand acknowledged: "It will be a hard game and we've got to make sure we bring our 'A' game because they've started very well in the group."
Bent is the fourth player to withdraw from the game with injury after Terry, Jagielka and Aaron Lennon (back) were also forced out.
Aston Villa's Stewart Downing and Gary Cahill of Bolton have been drafted into the squad as replacements.
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