His coach, Jim Harbaugh, worries that his new franchise quarterback may be becoming too strong, too fast.
"If you're just talking about weightlifting and upper-body strength, yes, I think there is that fear," Harbaugh said to Comcast SportsNet Bay Area. "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).
Kaepernick's arm certainly does not need to get any stronger. His throws the ball with plenty of velocity, to be sure. He dislocated Randy Moss' finger with one laser last season. And during Super Bowl week, 49ers teammate Michael Crabtree said some receivers would rather catch warmup passes from the other quarterbacks.