The 22-year-old has not played a senior game for the club since April last year because of the pelvic condition which prevented him from representing his country at last summer's World Cup finals.
However, Williams got 84 minutes under his belt for the reserves in midweek and is likely to travel to the Madejski Stadium.
Midfielder Julio Arca is battling knee and toe injuries and manager Tony Mowbray will make a late decision on him.
However, Andrew Davies, Matthew Bates, Justin Hoyte (all hamstring), Stephen McManus, Jonathan Franks, Luke Williams (all ankle), Danny Coyne (double hernia surgery), Willo Flood (thigh) and Kevin Thomson (hairline fibula fracture) are still out.
Source: PA
