Instead of entering his second NFL season as the frontrunner to start at weak-side inside linebacker, Brown is competing for a role behind Mosley. Mosley is ranked ahead of Brown on the depth chart with the first-round draft pick from Alabama regarded as the early favorite to start next to veteran middle linebacker Daryl Smith.
The competition between Mosley and Brown remains active, though. Brown is expected to divide playing time with Mosley, a consensus All-American selection last year who won the Butkus Award as the nation's top linebacker.
"C.J.'s a great player who's come in here and taken on a role and is learning fast," Brown said. "He has the talent, so there's a good opportunity for him. The coaches have said that it's a competition and we all have to be ready. We're interchangeable. I'm sure there will be playing time for both of us."
Brown has worked diligently to add bulk to his stocky, 6-foot frame, spending countless hours in the Ravens' weight room. Listed at 235 pounds, Brown said he currently weighs 232 pounds and has gained roughly seven pounds from where he finished last season. Brown doesn't appear to have lost his speed despite the weight gain.
"I've got to maintain this weight," Brown said. "It feels good, I feel fast at this weight. That's very important. A key part of my game is my speed. I worked on my physical strength and added some muscle mass. It's been very beneficial.
"I feel like I've done a lot to improve my body to get ready for this season. I feel like the strengths of my game are explosiveness, speed and being a sideline-to-sideline defender who has great instincts to get to the football."
After being drafted in the second round last year out of Kansas State, Brown spent the majority of his rookie season being utilized in pass coverage as a nickel linebacker. The former Big 12 Conference Defensive Player of the Year recorded 15 tackles, a half-sack and a forced fumble in 14 games last season.
"Absolutely, Arthur is playing better now than at any point last year," linebackers coach Ted Monachino said. "As a cover linebacker, still can be dominant down-in and down-out, but as a run-game linebacker, he’s playing very well. What you see out of him is the result of a lot of great preparation in the offseason.”
Brown was an All-American, a two-time team captain and a two-time All-Big 12 selection who registered 201 tackles, 16.5 for losses, three sacks and three interceptions during two seasons at Kansas State after transferring from Miami.
Brown tried to glean as much knowledge as possible during his first NFL season to prepare for a larger role this year.
"My rookie year was great for me," Brown said. "It was a learning experience. I laid the foundation that I'm building on this year."
Brown's not conceding anything to Mosley, who's drawn heavy praise from the coaching staff for his instincts, range and explosiveness.
"Training camp is always a way to get better, and I'm getting better every day," Brown said. "We have a lot of depth and talent at linebacker. C.J. and I are both a big part of what we're doing. I'm competing every single day."
The Ravens signed Smith to a four-year, $16.1 million contract in March. Smith, 32, is expected to play at least a few more seasons.
The Ravens could have set into motion an eventual succession plan where Mosley could mature into the middle linebacker role with Brown playing opposite him in the future at weak-side linebacker.
"No doubt, I know the coaches always have a long-term perspective in mind," Brown said. "I'm just focused on getting better every day. I came with very high expectations, so I don't want to do anything to limit myself. I'm setting high goals every day."