The 49ers don't expect wide receiver Danny Gray back for the start of the regular season.

Gray injured his right shoulder on the opening kickoff of their preseason game against the Broncos this weekend and head coach Kyle Shanahan said on Sunday that the team initially believed Gray suffered a broken collarbone. It turned out to be a sprained SC joint, which is a less severe injury but one that will still keep Gray out for an extended period of time.

"It doesn't sound like he'll be ready at the beginning of the year," Shanahan said, via Nick Wagoner of ESPN.com.

Gray was a third-round pick last year who appeared in 13 games for the 49ers. His injury comes a little more than a week after Ray-Ray McCloud broke his wrist, so the 49ers have two prospective members of their receiving corps on the sideline heading into the regular season.