49ers’ young wide receivers ‘spinning’ with new information in NFL training camp

SANTA CLARA — Being a rookie wide receiver in the 49ers’ offense is a tall task, and while there are a few who have stood out, coach Kyle Shanahan knows there is a significant amount of work yet to be done.“They’re spinning right now,” Shanahan said on Sunday after the 49ers completed their fourth practice of training camp. “Once you think you’ve got it, it gets a lot worse the next day.”With Brandon Aiyuk’s timeline to return uncertain, Demarcus Robinson facing up to a three-game suspension and Jauan Jennings leaving practice early due to a calf injury, there will be opportunities for younger players to see the field. How well they perform in the next few weeks will show who has been doing their homework. “Today was our first call-it period, which means it wasn’t scripted, so they have no idea what’s coming,” Shanahan explained. “I think that showed a little bit of rust. I think they’re in their playbooks, but they definitely can’t be content with it. They’ve got to get into more, they’ve got to get more of these...