The Scot had admitted that he was surprised about the center back's international recall after being left out of the squad for Euro 2012 and hinted the 34-year-old may not be fit enough for release.
However, the Red Devils boss has now confirmed that his defender will definitely join up with the Three Lions squad for the games against San Marino and Montenegro after an impressive display in the 1-0 victory over Reading.
When asked if Ferdinand would be in the England squad, he told ESPN: "Yes."
"We've always known Rio has the ability to break forward into midfield with his ability on the ball," he continued. "Obviously he doesn't do it that often these days, but nonetheless he did it today and got us a goal."
Wayne Rooney's deflected strike after 20 minutes was enough to give a below-par United side the win against the managerless Royals, and sees it extend its lead over Manchester City to 15 points.
The 71-year-old insisted the league leaders did not underestimate their opponents but admitted their own performance was not one of their best this term.
"They're down at the bottom of the league, so we expected [them to come out fighting]," he continued.
"Some of their football was very good. But they didn't really make any chances and all their danger came from where we expected - set pieces. We did defend quite well.
"We don't [play bad] that often. Most of the time we have played well this season. It has been a great season for us. The performance today didn't really reflect that we're 15 points ahead."
Sir Alex made eight changes from the Red Devils' last outing and indicated that his aim was to keep his players fresh with the international break in mind.
"That was the idea," he added. "We've got players who will be playing internationals. Chicharito has got to go across to Central America where he as two games.
"Antonio Valencia has two games also. It's the travel as much as anything. We have six England players going away with them, so it was a good opportunity to rest some."