SANTA CLARA, Calif. -- Even before this year's training camp started, the safety position appeared to be one of the thinnest on the San Francisco 49ers' roster, at least in terms of proven depth.

Less than a week into camp, that depth has already been put to the test. Free safety Jimmie Ward suffered a hamstring injury in the team's conditioning test and is expected to be out until around mid-August. Strong safety Eric Reid had a less serious ankle injury and is considered day-to-day. Reid has already begun doing individual drills, though the Niners probably won't rush him back for fear of making the injury worse. Then, Jaquiski Tartt, deemed the top backup to both Ward and Reid, suffered an apparent rib/oblique injury on Monday.

For the rest of that practice, the Niners patched together different combinations of young veterans Vinnie Sunseri and Don Jones and undrafted rookies Lorenzo Jerome and Chanceller James at safety. In Wednesday's practice, it was Sunseri at strong safety and Jerome at free safety with the starters.

On one hand, the injuries are disappointing because Ward, Reid and Tartt need all the work they can get in coordinator Robert Saleh's new defense. On the bright side, the chance to develop depth at a position that needs it could be expedited by the injuries.

The early returns indicate that James and Jerome, in particular, have been embracing their opportunity. Every practice seems to feature at least one big play from either player, with Jerome working mostly at free safety and James working primarily at strong safety, though James offers the versatility to do both.

"We were impressed with them on tape coming out of college," coach Kyle Shanahan said. "That's why we wanted them here. Then to get them -- you don't really know what you got until you're around them. When you're around guys who are pros and really study it and really pay attention in the meetings -- and even though they don't get all the reps -- if you're not a special type of guy who's not drafted and you're not studying in the film room all the time, when you get those few reps it's tough to be on it.

"Those are guys who really work at it off the field. So, when they get in, they take the most out of their opportunities and it gives them a chance with our team."

Back in the spring, the Niners brought in a handful of veteran safeties for workouts. Three-time Pro Bowler Jairus Byrd was among those brought in for a look. But the 49ers were apparently comfortable with what they had in place, or at least enough to take a longer look at some of their lesser-known names before bringing in more competition.

When injuries hit other positions recently and the Niners waived linebacker Jimmie Gilbert (ACL) and receiver B.J. Johnson (hamstring), the team still opted not to bring in another safety. Sure, that can be largely attributed to the belief they'll get Reid, Ward and/or Tartt back relatively soon, but it can also be taken as a vote of confidence for what's already in place.

And if that's not enough, the 49ers have other internal options, such as cornerbacks Will Davis and Adrian Colbert, who have experience at safety and could make the move. Colbert actually took some snaps at free safety in Wednesday's practice and even came up with an interception after an offensive miscommunication.

"You know, everyone could be a possibility, and that's something we'll discuss," Shanahan said. "When you lose three guys like that -- we know Eric Reid is day-to-day, I'll find out about Jaq -- but it gave a couple other guys some opportunities like Lorenzo, and Vinnie, Chanceller James. But, yeah, as those numbers start going, we need some more people in there just to get through camp, and whether you adjust a corner or whether you end up signing another guy, it really depends how long those guys are going to be out."