Ed Szczepanski-USA TODAY Sports

Ed Szczepanski-USA TODAY Sports

While there are still questions regarding who will start across from him, Tramaine Brock has unofficially had one of the two starting cornerback positions for the San Francisco 49ers locked down since the team's offseason program started.

What makes that so interesting is how quietly impressive he has been this offseason. There hasn't been a lot of chatter surrounding Brock since the offseason started, which is a good sign that his starting status is not in danger. Brock goes into the season as the second-highest rated defensive back on the team according to advanced statistics site Pro Football Focus, behind only Jimmie Ward who is reportedly the leader in the competition for the other starting spot. In Brock's defense, that ranking is based on 2015 statistics and Ward's grade is based off of 345 fewer snaps. Brock's coverage grade was significantly higher than his run support grade and the highest among all 49ers defensive backs.

How did Brock do during Friday's practice? "Played like a shutdown corner," said Grant Cohn of the Press Democrat. "Intercepted a deep pass intended for DeAndre Smelter. Pinned Smelter against the sideline and dove to the ground to pick off the throw. This was the only throw that came Brock's way."

"The veteran defensive back was not fooled by the very same stop-and-go route that Smelter caught earlier in the day," said Taylor Price of 49ers Media regarding the same play. Chris Biderman of Niners Wire says that the play energized the rest of Brock's defensive teammates as they erupted along the sideline following the interception.

"I can't let [Brock] make the interception, first of all," Smelter said following practice. "I got to try to break it up. I did (try), but I got to do better at that."

"Brock's quietly had a very good camp," says Biderman. "He hasn't been targeted often, and when he has, the coverage has been tight against San Francisco's inexperienced receivers."

The 49ers coaching staff has been equally impressed with Brock during the offseason. "He's one guy who's really jumped out to me," said defensive backs coach Jeff Hafley last month.

Brock, who missed 13 games in 2014 after appearing in every game the year before, has been working this offseason to get better and avoid injuries. He even told 49ers Media that he has taken up yoga. "Flexibility, stamina, all of that," Brock answered when asked how it helps his game. "It's been helping right now. I feel better." He is often joined by teammate Bruce Ellington.

In July, Pro Football Focus ranked the 49ers secondary as the 17th best in the NFL. It was the team's highest rated group within that series of rankings. "Much of the 49ers' roster struggled last year, but the secondary fared well for the most part," explained Matt Claassen. "Recent draft picks Ward and Reid have performed above-average, even though they may have not yet shown enough to live up to their first-round status. Brock didn't come close to his career-year of 2013, but had a solid season after missing most of the 2014 season."

A month earlier, in a different group of rankings, Ben Stockwell of Pro Football Focus ranked the team's cornerbacks alone as the 14th best in the NFL. "Tramaine Brock, Dontae Johnson, and Jimmie Ward all graded well, with Brock surrendering more than 75 yards only three times, while Ward added 21 stops from the slot," said Stockwell.

"My mindset is real different this year," Brock told 49ers Media in May. "I'm going back to the roots and just working." Brock appeared in 15 games last season and recorded three interceptions and 11 passes defended.