Earlier this month, an independent hearing officer found Callaway not responsible of sexually assaulting a female student.
Callaway, a sophomore from Miami, was accused of sexual misconduct by the woman in December. The woman and her witnesses boycotted Callaway's student conduct hearing in Gainesville because the university appointed a Gators football booster to adjudicate the case.
According to the ruling made by Jacksonville, Florida, attorney Jake Schickel, Callaway was cleared of three violations of Florida's student conduct code: conduct causing physical injury or endangering another's health or safety, sexual assault and sexual misconduct.
Callaway had 35 catches for 678 yards and four touchdowns as a freshman last season and returned two punts for touchdowns.
"We're fired up to have Antonio in the lineup," quarterback Luke Del Rio said. "He's done a tremendous job in practice. He's been consistent every day and worked really hard to get it shape. And when he came back, we embraced him with open arms and he's done a great job getting back into the groove. It can be difficult for some people.
"Definitely going to be an advantage to have him out there because he's such a great player both on offense and on special teams. It will be fun."
The Gators will have at least five players suspended for the opener.
Freshman receivers Tyrie Cleveland and Rick Wells won't play because they are facing felony charges for allegedly firing BB guns into a residential hall last month. All-Southeastern Conference cornerback Jalen Tabor and tight end C'yontai Lewis will join them on the sideline. They were suspended for fighting in practice. And McElwain said one senior -- he declined to name him -- won't play.
"You know, we've had some guys that obviously made some choices not to play in this game," McElwain said. "Those guys will join us when the time's ready."
ESPN Staff Writers Brett McMurphy, Mark Schlabach and The Associated Press contributed to this report.