Craig Dahl preseason 49ersThe 49ers’ defense got to square off with one of the best quarterbacks in the NFL on Thursday and for a fleeting moment, it was glorious. Much like the 49ers, the Denver Broncos rolled out their most bland offensive scheme for Peyton Manning and his offensive cohorts, who couldn’t make much noise on San Francisco’s first team defense.

The defense we saw on Thursday was probably a less accurate depiction of what the 49ers will trot out than what we saw on offense. Several players were absent while other positions remain in flux. Demarcus Dobbs was playing in place of Justin Smith and Michael Wilhoite started in place of Patrick Willis. Then there was Craig Dahl, who started with the first teamers before ceding the position to Eric Reid. Tramaine Brock started the game as the corner opposite Tarell Brown, although his spot is up for grabs as well.

The starting defense only got a handful of plays against the Broncos’ first team offense, allowing one first down before forcing a punt. Denver ran some no huddle which seemed to leave the 49ers a little off-kilter, but they did well overall.

Safety

– Dahl didn’t get targeted so his abilities in coverage were never in question. He looks like he’s a quality backup, but he doesn’t strike fear into the hearts of opposing offenses.

– Dahl did a nice job jumping into a play to stuff Ronnie Hillman on a run off tackle. It was about the only play that stood out from him.

Tramaine Brock 49ers preseasonCornerback

– The 49ers are going to have a tough time if Brock is one of their two starting cornerbacks. He gave Demaryius Thomas too much of a cushion on an easy dig route. Manning stared Thomas down from the onset and Brock was still late getting to the ball.

– It wasn’t all bad for Brock. He did a nice job staying with Thomas deep on a sideline route. He broke up the pass on second down and Denver was forced to punt two plays later.

– Nnamdi Asomugha played like a man with something to prove. He sat back on third down and crushed Gerell Robinson after Brock Osweiler threw the ball high.

– Asomugha did a good job of shedding a blocking wide receiver to stop Montee Ball on the Broncos’ third drive.

– Perrish Cox was a standout player on Thursday. He flashed defensively on a few occasions and had a nice kick return as well as a 15-yard punt return.

– Cox jumped a route late in the second quarter and nearly intercepted an Osweiler pass.

Defensive line/Pass rush

– It will be important for Justin Smith to stay healthy this year if the reps from Dobbs are any indication. The interior defensive line provided almost no pressure on Manning, and Dobbs was stood up at the line on more than one occasion.

– Aldon Smith looks to be in midseason form. He pressured Manning on his final offensive play by pinning his ears back and bull-rushing. He also did a great job of scraping behind the line of scrimmage to follow and assist on tackling Hillman.

– Ian Williams drew a hold on the Bronco’s second drive after penetrating well and getting interfered with by Denver’s center.

Linebackers

– Shocker: Navorro Bowman looks as good as ever.

– Parys Haralson looks to be back in pre-injury form. He played well in replacement of Ahmad Brooks. Both outside linebacker positions are probably sewn up, but Haralson will be an important relief player.

– Corey Lemonier (AKA Mini-Aldon) showed some of the reasons why the 49ers jumped up in the draft to get him. He’s got great length and speed. He could definitely be a factor, perhaps not this season, but in the future.

– Michael Wilhoite played a lot like Larry Grant did in the past. He should be a suitable backup for Willis because, let’s be honest, nobody can really replace him.