Jim Harbaugh, Vic Fangio discuss guys who could see some added playing time on Thursday

The 49ers open up their preseason schedule on Thursday, and with starters likely to get fairly limited reps, the backups will get a chance to show what they can do.

Earlier today, Coach Harbaugh made an appearance on the Murph & Mac Show on KNBR, and defensive coordinator Vic Fangio addressed the media at camp this afternoon. Both mentioned some players who will likely see a lot of snaps on Thursday.

Coach Harbaugh indicated A.J. Jenkins will see plenty of snaps against the Broncos, which is not exactly a surprise. Reports indicate he has looked sharper in practice the last couple days, but it's all about showing it in games when it matters most. Vic Fangio used a good analogy, describing practice on the field like a quiz, and performance in the game itself like a test.

Speaking of Fangio, he stated that Marcus Cooper would likely see a decent number of snaps. According to Fangio, Cooper has been "doing fine" in practice, and has actually picked it up to some extent in recent sessions. Fangio said Cooper looked more comfortable with his assignments and in his technique. The more comfortable he can get with that, the better he can handle the speed of the game this Thursday. Chris Culliver's injury threw the cornerback position battle for a bit of a loop, and opened the door for someone further down the roster. Cooper has a lot of work to do, but his chances improved at least a little bit.

Fangio also indicated Tramaine Brock will get plenty of opportunities on Thursday. Although it would appear he'll be coming in as a so-called starter in the team's nickel defense, I imagine he'll stay in when Tarell Brown and Carlos Rogers sit. I would guess the second-team defense will feature Brock on the left, Nnamdi Asomugha on the right, and then Perrish Cox in the slot.

Fangio was asked about Lawrence Okoye's development and preseason playing time. He said the defensive lineman has shown improvement, but he also made sure to add the context of it being relative to where he started. Given that he never played a down of football before this summer, there was nowhere to go but up.

Fangio would not guarantee playing time for Okoye largely because it depended on how much the defense was on the field. If the Broncos offense is going three and out, and the 49ers offense is rolling off time-consuming drives, there are going to be fewer opportunities for defensive snaps. I would be surprised if Okoye didn't get even a few snaps, but hopefully he ends up out there for two or three series.

As we look toward Thursday's game, aside from the Jenkins and Okoye, which non-starter will have your eye as the 49ers roll out virtually the entire depth chart over four quarters? Eric Reid will obviously be a guy to watch after Craig Dahl leaves the game, but let's go beyond the obvious.

On offense, MarQueis Gray is a guy I'm curious about, and the D.J. Harper-Jewel Hampton competition will be worth tracking. I also want to see what Kenny Wiggins brings to the table in comparison to Adam Snyder.

On defense, I want to see what Cam Johnson and Corey Lemonier are able to do. I also am curious how Michael Thomas looks covering the slot. Right now, although he's listed as a safety, he is also the third-string nickel back.

Who will you be tracking on Thursday?