The 49ers could start the season with three former first-round picks on their four-man defensive line.
The exception? Nose tackle Earl Mitchell, a former third-round selection who went largely unnoticed when San Francisco was going through non-contact practices in the spring but who jumped out as soon as the pads went on earlier this week.
Coaches this summer must pick a starting center between Daniel Kilgore and Jeremy Zuttah. So far both have had a hard time blocking Mitchell, especially in one-on-one pass-rush drills.
"He's not huge, but he's quick off the ball," Zuttah said. "… Just him being able to get into you before you're set is an advantage for him.