"I don't waver that Sam is our starter," Wilks said Saturday. "It is his job to lose."
Bradford, who signed a one-year, $20 million contract in March, appeared in just two games with the Minnesota Vikings in 2017. He went on injured reserve and had arthroscopic surgery in November before being activated as Case Keenum's backup during the postseason.
Wilks said Bradford's knee is "stronger than it has ever been" -- a point with which the top overall pick in the 2010 NFL Draft concurred.
"It's definitely the best it's felt since the injury last year," Bradford said. "My body's in a good place and I think we'll see the benefits of the plan we had throughout OTAs and throughout the spring."
Glennon is with his third organization in as many years. A third-round pick of the Tampa Bay Buccaneers in 2013, Glennon lasted only four games as the starter with the Bears before he lost the job to rookie Mitch Trubisky, the No. 2 overall selection in 2017.
He could have a similar struggle winning the backup job against Rosen, who was drafted No. 10 overall by Arizona after it traded with Oakland to move up five spots in April.
Rosen passed for 9,301 yards and 59 touchdowns with 26 interceptions while playing in 30 games in three seasons as UCLA's starting quarterback.
Wilks said he expects Rosen, who passed for 3,754 yards and 26 touchdowns with 10 interceptions in 2017, to compete for the starting job, but that holds true at every position.
"Competition makes us better across the board, so I think it's only going to make us better," Wilks said.