Film review: Culliver ready to pounce on starting job

Cornerback Tarell Brown sat out last Wednesday's practice due to a slight hamstring ailment. He returned to practice the next day, and was available for Sunday's game against the Miami Dolphins.

It was a wise move.

Jim Harbaugh has been reluctant to make lineup changes in two seasons as 49ers coach. Guard Chilo Rachal is the only player benched due solely to poor play.

But Harbaugh has made several changes after injuries. And quarterback Alex Smith does not stand alone.

Bruce Miller took over at fullback for veteran Moran Norris due to an injury last season and he held onto the job. Shawntae Spencer lost his starting job and then his role as the No. 3 cornerback due to an injuries. Tramaine Brock, who opened last season as the No. 3 cornerback, sustained an injury that opened the door for Chris Culliver, who has remained in that role.

And, now, Culliver is playing at a starter's level. If Brown or Carlos Rogers ever exit the lineup, Culliver would have a chance to take over -- and then hold onto -- a starting job.

Rogers got off to a slow start Sunday against the Dolphins with an apparent miscommunication on Miami's second play of the game that resulted in a game-long 28-yard pass play.

Rogers and Brown have started every game for a defense that No. 2 in the NFL against the pass. And both had solid showings Sunday in a defensive effort that held rookie quarterback Ryan Tannehill to 17-of-33 passing for 150 yards with one touchdown and no interceptions.

But Culliver, who played 70 percent of the snaps as the 49ers' third cornerback, had another outstanding game. He was targeted four times and did not allow a catch, according to Pro Football Focus. He had the defensive play of the game when he hung in the air long enough to deflect Tannehill's deep throw to Brian Hartline in the end zone. Culliver's 42.9 completion percentage allowed this season ranks as the best in the NFL, according to PFF.

Other observations from the 49ers' 27-13 victory over Miami:

--Outside linebacker Aldon Smith, who has quickly risen to the short list of NFL Defensive Player of the Year candidates, had four quarterback hurries to go along with his two sacks.

--Neither of Aldon Smith's sacks was a direct result of any help from Justin Smith, who was busy causing all kinds of problems of his own for the Dolphins. Justin Smith was particularly impressive at the start of the second half when he batted down a pass at the line of scrimmage on second down and then destroyed guard Richie Incognito to pressure Tannehill into a third-down incomplete pass.

--Safety Dashon Goldson did not have a strong game, as he overran a couple of would-be tackles. He took a bad angle and allowed Tannehill to get past him for a 20-yard scramble in the fourth quarter. He also got flattened by center Mike Pouncey on a 9-yard gain by Reggie Bush. Goldson's best play was in coverage against Bush on a deep right along the left sideline.

--Linebacker NaVorro Bowman, fined $10,000 last week for unnecessary roughness, could be looking at another fine this week for his helmet-to-helmet hit on Tannehill in the fourth quarter. It drew a 15-yard penalty.

--The 49ers' only touchdown allowed came on a play in which tight end Anthony Fasano made a highlight-reel one-handed diving catch against the sideline in the end zone. It's difficult to fault the coverage of safety Donte Whitner on that one.

--On offense, the 49ers featured a lot of balanced offensive formations with Colin Kaepernick in the pistol along with three backs.

"We thought in this particular game, that it was a way for us to get a hat on a hat," Harbaugh said. "A way to balance off Miami's defense and what they had shown to do. Because it is a balanced formation, it allows you to go in any direction and throw the ball. It was a good, basic, base formation for us in this game."

The 49ers used it on the first play of the game to hit Delanie Walker on a 20-yard reception.

--Kaepernick had only two pass plays for 20 yards or more. The pass to Walker traveled 17 yards in the air, and a 25-yard gain to Michael Crabtree included 7 yards after the catch.

--The only pass Kaepernick has thrown the past two weeks at least 20 yards in the air, according to PFF, was the flea-flicker to Randy Moss. The ball was perfectly thrown, but Moss seemed to have very little chance of making the one-handed catch with cornerback R.J. Stanford grabbing Moss' right arm.

--Kaepernick was 18 of 23 for 185 yards. His five incompletions consisted of: 1) A bullet off Vernon Davis' hands at the left sideline against good coverage. The throw was high and wide and too hot for Davis to handle; 2) A high-and-outside throw toward the right pylon to Crabtree that, if accurate, likely would've been a 20-yard touchdown pass; 3) A wise throwaway at the end of the first half to allow David Akers time to kick a 37-yard field goal; 4) The deep throw to Moss, which could've been a 47-yard TD; and 5) A quasi-throwaway just before running out of bounds on a roll to his left late in the third quarter.

--Crabtree was targeted 10 times and caught nine passes. Fifty of his 93 receiving yards came after the catch.

--Left tackle Joe Staley graded out with a strong performance, according to PFF. He surrendered one sack but did not allow any other pressures. According to PFF's rating system, Staley has not had a negative grade in any game this season.

--Running back Frank Gore looked fresh and routinely made Dolphins defenders miss. His used an exceptional jump-cut to peel off a 19-yard gain late in the third quarter. Due in large part to Miami's focus on Gore, Kaepernick was able to keep the ball on a zone read play in the fourth quarter for a 50-yard, game-clinching touchdown.

--On the first play of the fourth quarter, Gore ran 19 yards on a draw play to the 1-yard line. Guard Alex Boone made a strong block on defensive tackle Paul Soliai and rookie receiver A.J. Jenkins had a block against safety Chris Clemons.

--On the next play, extra blocker Daniel Kilgore absolutely mauled defensive end Olivier Vernon and Miller took care of safety Reshad Jones on Anthony Dixon's 1-yard touchdown run.