The San Francisco 49ers' second-year linebacker, Fred Warner, spoke with reporters last week. He started 16 games during his rookie campaign while racking up a team-leading 124 combined tackles, six passes defensed, and a forced fumble.

A lot is expected from Warner during his sophomore campaign. He has already established himself as one of the team's best young players. The question thrown at Warner last week was who he sees as a potential sleeper in 2019.

Warner thought about the question for a moment and then responded.

"The guys who have been here, there's a lot of guys who have stepped up," Warner said. "But somebody who has been flying under the radar I think should be mentioned is Alex Brown, a corner that's came in. He's done an outstanding job. He's shown up on tape to me.

"Obviously, everybody knows that [DeForest Buckner] and guys like that, they're taking the game to the next level. But I think Alex has kind of flown under the radar. He's been doing an outstanding job."

Brown participated in the 49ers' rookie minicamp after the draft (which is when the photo above is from), and the team signed him on May 16.

The undrafted free agent out of South Carolina State recorded 90 tackles, 26 passes defensed, seven interceptions, and one sack in 31 games with 25 starts during five seasons with the Bulldogs. Brown started all 11 games in 2018 while recording 42 tackles, eight passes defensed, four interceptions, and one sack.

As for Warner and his expectations heading into his second NFL season, he knows there is room for improvement even after his impressive rookie year. That valuable experience from last season has helped Warner identify flaws in his game. While watching film, he can spot plays where he wishes he had done things differently.

Warner has been sidelined this offseason after undergoing a clean-up procedure on his knee, but the coaching staff expects him to be full-go by training camp.

What did he focus on improving this offseason?

"Having that experience from year one, obviously playing a lot of snaps, I think all parts of my game can improve," Warner said. "Specifically, I'm looking forward to working on tracking the ball, making sure that I'm improving on tackling, just communication, having clean eyes, being able to anticipate stuff a lot quicker. So, a lot of things."