Sunday will be far from a day of rest for the San Francisco 49ers. The first two practices of camp featured minimal differences from what we saw during the offseason program. Not that the sessions didn't hold value, but there's only so much that can be accomplished in shorts.

That will change on Sunday when the 49ers suit up in full pads for the first time this summer. Everyone knows that camp doesn't officially start until you hear the first collision.

"(I'm) very eager," Kyle Shanahan said on Saturday. "I think everyone is. We've seen enough in OTAs of what our guys can do without pads. That's how it was yesterday and today. Tomorrow's a little bit different. It's really when it starts."

Players are equally ready for an uptick in the competition level. It serves as an opportunity to separate yourself in a more realistic environment. Highlights don't count until plays are made with shoulder pads on.

"It's an attitude," linebacker Elvis Dumervil said. "When the pads come on, we separate the men from the 't-shirt guys'."

Two of the marquee padded drills are running back blitz pickups and pass-rushing 1-on-1s. That means we could see NaVorro Bowman barreling down on rookie running back Joe Williams or Dumervil trying to beat Joe Staley 1-on-1.

The moments of personal pride carry into the skill positions as well. Matchups between wide receivers and corners will be much more physical.

"I get to jam more," Rashard Robinson said. "I get to jam and 'thud up'. There are going to be more juices going. You're going to hear some loud collisions. We're here. We're balling. The defense is ready, the offense is going to be ready and I know the coaches can't wait."

It's fair to say that position battles will truly begin on Sunday. Which offensive linemen separate themselves? Will Dontae Johnson or Keith Reaser emerge as the team's No. 2 cornerback? Which tight end rises to the occasion? We may not be too far away from some of those answers.