The Swiss defender is set for his first start at home in the Premiership in almost a year against Manchester City on Saturday.
Manager George Graham said: "The options are Luke Young, who is coming back from injury as well, Ramon Vega and young Alton Thelwell.
"Ramon is big, attacks the ball in the air, is very dangerous at set-pieces and probably needs a couple of good performances to boost his confidence because he's not played on a regular basis for a long time. It's his chance to show he has a future here.
"Young Thelwell is a good defender and that is unusual, because he is a defender. It's unusual saying that. He's a defender who likes to defend and there are very few around in the country."
Ledley King and Anthony Gardner would also be in the frame but for injury. King played his first 90 minutes since breaking his foot in May last week but Gardner is yet to return after a thigh problem.
Campbell is expected to be out for up to six weeks after undergoing minor keyhole surgery on Saturday.
Otherwise the news on the injury front is good. Darren Anderton is making rapid progress after his groin injury, Young is available after his foot was diagnosed as bruised, not broken and Chris Armstrong, Willem Korsten, Jose Dominguez and King are all playing again.
George said of Anderton: "Darren is doing some light training. He's now jogging pain free and now it's about striking balls again."
City face losing influential defender Gerard Wiekens after he limped off against Middlesbrough last week with an Achilles injury.
Fellow defenders Paul Ritchie (groin), Danny Tiatto (flu) and Steve Howey (ankle) and midfielder Kevin Horlock (ankle) are expected to pull through.
Ramon Vega looks to have won the race to replace Sol Campbell.