Extra innings: Maddon believes Carl Edwards Jr. can develop into a closer. "There's no question he's got that ability," Maddon said. "Right now he's around some good mentors, and that's very important. He's keeping his mouth shut and all eyes and ears." Edwards converted his only save opportunity at Triple-A Iowa before his promotion to the Cubs on June 20. ... Several players attended a Kenny Chesney concert at Levi's Stadium in Santa Clara on Saturday night and were treated to a tour of the 49ers' training facility by coach Chip Kelly.