"Two great players. Chris Borland came on strong for us towards the end of the year, but we've got to keep it rolling. I'm pretty sure we're going to have guys that are going to step in and play some great football for us."
The 30-year-old Bethea isn't worried about importing a new coordinator in Eric Mangini or having to replace two more starters in his secondary, because he believes the players next in line are ready to make the leap.
"It's going to be fine," Bethea said. "I have no worries about that. I think last year, I think there was a lot of talk about our secondary, but I think our secondary did pretty good last year. We've got a lot of young guys.
"T-Brock (Tramaine Brock) is healthy and once we come together, get this camaraderie together out here working, pushing each other, get these OTAs, minicamps and all that, I think we'll be fine."
The 49ers led the NFL with 23 interceptions last season. With the changes in front of them, the back end might be asked to step up even more in 2015, even though they've gone through big -- albeit much quieter -- fluctuations themselves.