Fangio: Great learning experience for 49ers' defense

SANTA CLARA -- A year ago, quarterback Matt Schaub diced up the 49ers for 180 yards in the first half as the Houston Texans scored 24 points on the 49ers' first-team defense in the third exhibition game.
On Sunday, the first-team defense did not offer much resistance to Peyton Manning and the Denver Broncos.Playing without key defenders Aldon Smith, NaVorro Bowman and Chris Culliver, the 49ers had few answers for Manning, who threw for 122 yards. The Broncos scored 17 points on their three possessions against the 49ers.REWIND: 'Scary start' for 49ers defense against Broncos
"We just didn't play well enough on certain plays," 49ers defensive coordinator Fangio said. "I think it was a great learning experience for us. Some of the plays we broke down, we definitely could've played better. And in some instances, they just beat us one-on-one. We weren't able to win the one-on-one battles."This is still a great time to learn, perfect your craft (and) excel on your technique. We have to be able to do that. We weren't perfect on that the other night, by any means."With Culliver out, the 49ers turned to Tramaine Brock as the team's No. 3 cornerback. Brock sustained a broken finger a couple weeks ago, but it's nothing that is impacting his play, Fangio said.When asked for his evaluation of Brock's play, Fangio answered, "He's played better."Perrish Cox has seemingly surpassed Brock on the depth chart, and figures to find a role once the regular season begins. Cox is currently the No. 2 nickel back behind Carlos Rogers and a spare corner."The more three- and four-wide receiver teams that we see, the more he'll get to play," Fangio said. "If he keeps playing the way he's playing and becomes an expert at his craft, we'll find a way to get him in there."The 49ers might use a fourth cornerback in packages against teams that put four receivers on the field. Fangio said a third safety has yet to step up behind starters Dashon Goldson and Donte Whitner, but he noted Trenton Robinson, Darcel McBath and C.J. Spillman are showing improvement.The 49ers' No. 1 defense has forced a punt on just one of their seven series in the exhibition season. The opposition has scored 26 points with four field goals and two touchdowns.Drives vs. 49ers first-team defense
Minnesota
6 plays, 59 yards, field goal
13 plays, 63 yards, field goalHouston
7 plays, 37 yards, field goal
3 plays, 9 yards, puntDenver
8 plays, 45 yards, field goal
9 plays, 83 yards, touchdown
4 plays, 24 yards, touchdownTight enddefensive lineman Demarcus Dobbs was seen walking through the locker room Monday on crutches with his lower left leg wrapped. He declined comment.Receiver Ted Ginn, who left Sunday's game with a right ankle sprain, wore an orthopedic boot on his foot. He was not using crutches. His status for the season opener, Sept. 9 at Green Bay, remains in question.Also, running back Brandon Jacobs is showing improvement after sustaining a left knee sprain Aug. 18 at Houston. He is no longer on crutches, but he was seen walking with a limp. The 49ers are hopeful Jacobs will be available for the season opener.