The Whites have Lucas Radebe and Michael Duberry both missing through injury, while skipper Dominic Matteo is suspended for Saturday and Gray hasn't many options to partner Matthew Kilgallon for the trip to Southampton.
The Brazilian World Cup winner returned to action for the reserves last night against Wolves at Telford and Gray is hoping the defender can rediscover the form which saw him win the World Cup with Brazil in 2002.
Gray said: "You don't play for Brazil at the World Cup if you can't play. It took some of the best players in the Premiership time to adapt to the English game.
"Roque Junior has looked good in training and is working on building up his fitness."