Colin Kaepernick almost immediately began his offseason training following the San Francisco 49ers' loss in the Super Bowl.
Jim Harbaugh has spoken to Kaepernick about not allowing himself to get too strong and bulky.
"If you're just talking about weightlifting and upper-body strength, yes, I think there is that fear," Harbaugh said.
"It's something we've talked about. 'I don't want you getting too jacked-up, Colin.' I want some speed, quickness, not just (flexing chest his muscles)."