Although Ferdinand had featured in three successive United games after recovering from the hamstring injury he suffered in the opening day win at West Brom in August, Fabio Capello decided the 32-year-old was not fit enough for England duty in Montenegro this week.
With an increasing number of younger central defenders - including club-mates Phil Jones and Chris Smalling - appearing on the scene, it raises a significant question mark over a player who has struggled with injury for three years now and has been involved in just 13 of England's last 35 games.
However, Welbeck has struck up a close bond with Ferdinand.
And the 20-year-old believes it is far to early to start dismissing a player of such vast experience.
"Rio is a Rolls Royce of a defender," said Welbeck.
"I train with him every day. I know the capabilities that he has. It is wrong to write him off."
Nevertheless, England will have to do without Ferdinand in Podgorica on Friday, when they require a point to seal a place at Euro 2012.
And, although it could be Capello's last qualifier in charge of the national side, the Italian is pointing towards a future filled with younger players, including Welbeck - who is vying with Andy Carroll, Darren Bent and Bobby Zamora for the right to partner first-choice front-man Wayne Rooney.
"There is great competition for the striking spots," said Welbeck.
"You come here to train with the best players and there is great talent all over the squad - there are great players who are not even here."
Merely being selected shows how much progress Welbeck has made since returning from a loan spell at Sunderland in the summer.
When he flew to the USA to join United's North American tour in July, Welbeck did so expecting to be Sir Alex Ferguson's fifth-choice striker.
Yet already he has nudged Dimitar Berbatov and Michael Owen out of the way, leaving just Rooney and Javier Hernandez ahead of him.
And, by taking his tally to six for the season with a brace on his Champions League debut against Basle, followed by the match-sealing second against Norwich on Saturday, Welbeck is showing no ill-effects from a hamstring injury he suffered in the eight-goal destruction of Arsenal in August.
"I was coming into my own a little bit, so I was devastated to pull up like that," he said.
"But I couldn't sit back and moan. I had to get into training every single day and follow the programme the physios put down for me.
"You've just got to come back flying, as you were before you got injured."
Welbeck has been doing plenty of work in the gym to build up his strength, which he noted when he filled out physically at Sunderland.
"I've literally grown into a man," he said.
"I have been doing a bit of gym work but it's more based around my legs. My physique is a lot better before I went away.
"I'm still only 70-odd kilograms and some of the centre-backs are 90, so I need to be strong."
It was assumed Welbeck was going to be part of Capello's starting line-up for last month's trip to Bulgaria before the hamstring strain intervened.
However, the striker sees no reason why such an opinion should have changed, especially as he has so much knowledge of Rooney's game.
"I don't see why Rooney and Welbeck can't work together as a pair for England," he said.
"We know each other's games and whilst it is early days, because we have been training together for a couple of years now it would work.
"Wazza has certainly been on fire. He has started the season scoring and creating goals and been a great team player as well.
"To be playing and training with him every day is a bonus.
"He is a great guy to go to for advice. He talks to you during games and in training. It is really beneficial.
"I have to learn from him and try to pick up as much as I can."