The centre-back was substituted towards the end of the 1-0 win over Fulham but it was only a precaution and he has had no after-effects to the back problem that troubles him from time to time. With Nani still not fit enough to return, the travelling party is likely to be unchanged from the one that saw off the Cottagers.
"It'll be the same squad as Monday night with no changes," stated the boss. "We expect Nani to train tomorrow but the game will come too soon for him. Rio is okay, he just felt a bit stiff. We know the situation with that. We addressed it right away and put Chris Smalling on. He's fine."
Sir Alex knows to expect a real battle at Ewood Park, which hasn't been the happiest of hunting grounds for the Reds over the years.
"The game at Blackburn is always a difficult type of game," he added. "It has a local derby feeling about it and is always a bit feisty. Last season, we came back from a goal down to win the league but we expect a difficult game. That's the way all the matches will be but hopefully we can navigate them."