“He almost made a hell of a play,” Shanahan said. “I thought he had a pick-six, just mistimed it and actually gave up the completion — but it was really good coverage.

“I was real excited with [Stout] in OTAs, and he is one of the guys where I think he’s got a chance to compete to help us throughout this training camp and into the season.”

The 49ers’ defense is filled with many such young players. The team must replace more than 40% of its 2024 snaps on that side of the ball, and Wednesday’s session marked the first time that all key rookie pieces practiced together. That’s because second-round pick Alfred Collins, who dealt with a calf injury in spring, is finally cleared to participate. At 6-foot-7, with a wingspan of more than 7 feet, Collins is easy to spot; so is defensive end Mykel Williams, whom the 49ers picked in the first round.