The 23-year-old played 28 minutes of the reserves' 1-1 draw with West Ham on Tuesday, his first taste of action since he damaged knee ligaments in August last year.
Neither he nor his manager will take any chances with his recovery, although Bruce is hopeful that he could be ready to play early next month with Liverpool's Barclays Premier League visit to the Stadium of Light on March 20 likely to come a little too soon.
On the way back: Campbell scores an FA Cup goal for Sunderland against Barrow last year
However, the former Manchester United defender knows from personal experience how difficult things can be psychologically after a lengthy lay-off.
He told the Sunderland Echo: 'You have always got to deal with the mental side of it. I remember when I broke my leg when I was younger and ended up trying to tackle with my other foot. You are always a little bit hesitant.
'You need a whack on it and all of a sudden, you are confident again and you know it's okay.
'It's very difficult for any player who has been out for such a long time.'
Campbell last played a senior game for Sunderland in the 1-0 win over Manchester City on August 29 and by coincidence, the fixture which immediately follows the clash with Liverpool sees the Black Cats head for Eastlands on April 3.
Bruce said: 'When you look at him, you wouldn't think he has been out for seven months.
'I have always had it in my mind that we have got two games in March. We have got two weeks after Liverpool until Man City, so I'm looking at that game rather than Liverpool.
'Hopefully we can get enough football into him that he can be ready to make an impact.'
Warning: Sunderland boss Steve Bruce
Campbell is delighted simply to have returned to the fold, but is putting no pressure on himself.
He said: 'There's no rush to come back. It's not about getting back for a particular game - I'll take my time and get back into the first team when I'm fit and ready to produce my best stuff.
'I want to play as much football as I can while being sensible and building my fitness up.'
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