Williams, 31, has not made an appearance in the first team this year after picking up a potentially career-threatening knee injury just after Christmas.
Speaking to Reading World assistant boss Kevin Dillon confirmed the good news. "Adie Williams is fit so he'll come back into the team."
More than 15,000 tickets have been sold for tomorrow's game against Leicester so a bumper crowd is anticiapted. Many more fans may buy a ticket on the night as they are available for half price due to the abandonment of the original encounter at half time on New Year's Day. A victory will move the Royals up to fourth in the league.
Meanwhile, Wales today announced their squad for the forthcoming friendly against Bosnia at the Millennium Stadium next month. However, due to his recent injury, there was no place for Adie Williams who had been in Mark Hughes' previous squad, for the qualifier in Azerbaijan.