Clearly in pain, Campbell was led back down the tunnel by physiotherapist Alasdair Beattie after just 31 minutes of the second round, first leg encounter.
Our super skipper went to hospital straight away but had returned to Griffin Park in time to leave with his team-mates after the 0-0 draw. It is believed he 'popped back' the dislocated shoulder on Tuesday night and he will now have further tests on Wednesday.
The injury came after Campbell challenged for a header with Brentford striker Mark McCammon and landed awkwardly.
It means he is likely to miss Premiership matches against Manchester City, Leeds and Coventry and on a wider scale looks set to be ruled out of England's opening World Cup qualifying matches against Germany and Finland on October 7 and 11 respectively.
Manager George Graham confirmed: "Sol has dislocated his shoulder. He will probably be out for three or four weeks.
"He's been to hospital and come back and he will go for further tests on Wednesday. He will have a scan to see what damage has been done but it doesn't look promising for the next three or four weeks at least.
"I thought we should have got a few free-kicks in the first 10 minutes against him (McCammon). I thought it was something that could have happened, maybe not to Sol, but the way it was going I thought earlier in the game we could have got those free-kicks. So it didn't surprise me what happened."
To listen to George's thoughts on Sol Campbell's injury, click here
Sol Campbell could be out of action for up to a month after dislocating his shoulder in Tuesday night's Worthington Cup tie at Brentford.