Ferdinand has missed United’s last two games, as he is looking to sort out his back injury.
“Rio has been injured for a very long time and he’s been getting a lot of pain in his back for a long time,” said Brown. “I’m not sure how many months it’s been going on, but he’s come to the stage where he’s sorting it out now.
“When he comes back, I’m sure he’ll be a lot stronger. If you are not fully fit and you try to play, it’s very hard, especially with how fast the Premier League is now.
“If you carry on playing with that same injury, week in, week out, it does make things even harder. That’s what happens and Rio has decided to sort it out.”
