Smalling, sidelined this term by a broken metatarsal, was included in United's travelling party for the game at the Estadio AXA having stepped up his rehabilitation in training.
And speaking at Tuesday evening's pre-match press conference, Ferguson revealed that he is intending for the England international to be "involved" on Wednesday.
Asked for an update on Smalling and fellow defender Phil Jones, who is also yet to play this campaign due to back and knee problems, Ferguson said: "Phil Jones will start training with us next Monday which is good news, he is making really good progress now.
"Chris Smalling is with the party and will be involved tomorrow [Wednesday].
"That is really good news because as we know, since the start of the season we've been operating on the borderline in terms of certain defenders having to play all the time, and also having to play (midfielder) Michael Carrick as a centre-back.
"They can only help us with that. Those two are outstanding young defenders and it will give us a fantastic squad to take on all our challenges."
Also missing the trip to Portugal along with Jones, defender Nemanja Vidic and midfielder Shinji Kagawa (both knee), are central midfield pair Darren Fletcher and Paul Scholes.
Asked about Fletcher and Scholes, who is 38 this month, Ferguson explained: "Fletcher had a little bit of a cold on Sunday and there is no point in taking him travelling with a cold.
"With Scholes, for the last few weeks I have been resting him, looking to freshen him up a bit. I'm just taking care of an old man, that's all!"
Ferguson day celebrated the 26th anniversary of his appointment on Tuesday and Braga coach Jose Peseiro congratulated him on his longevity - but is confident there will be little for the Scot to celebrate when the two teams meet on Wednesday night.
Peseiro said: "He is a fantastic coach and an example to any coach with his quality. I have spoken with him a few times and you can learn so much in just 10 or 15 minutes speaking with him.
"Congratulations to him, but tomorrow [Wednesday] I think he will go back to Manchester no happier."
Peseiro said his team - who raced into a 2-0 lead against United at Old Trafford last month before eventually going down 3-2 - do not fear the Red Devils, emphasising that he and his players are relishing their opportunity to come up against such opposition and enjoying the hype that comes with it.
"Manchester United are a fantastic team and (to play them) is fantastic for me and all the players," Peseiro said. "If you play against Manchester United, this is the maximum.
"I would like to go and work in England, like my players, because everybody there likes their football."