SANTA CLARA, Calif. -- Playing safety for the San Francisco 49ers these days is apparently anything but safe.

After projected starting free safety Jimmie Ward suffered a hamstring injury during the team's conditioning test last week and strong safety Eric Reid departed with an ankle injury Sunday, Jaquiski Tartt joined the list of the walking wounded in Monday's practice.

The extent of Tartt's injury wasn't yet clear after practice, but coach Kyle Shanahan said it seemed to be a rib issue. How much time Tartt will miss, if any, remains to be seen. Reid's injury is considered day-to-day, so he should be back soon enough while Ward could miss extended time.

Regardless, the 49ers are now thin at safety. Ward, Reid and Tartt are their three best players at the position and there isn't much experience behind them. After Tartt left Monday's practice, the 49ers worked with various combinations that included Vinnie Sunseri, Chanceller James, Lorenzo Jerome and Don Jones.

Sunseri and Jones have been around but rarely done more than contribute on special teams while James and Jerome are undrafted rookies. James and Jerome have flashed potential, though, and are now getting even more opportunities as this camp progresses.

If Tartt does have to miss some time, the Niners could look to the outside for more depth or look internally, where guys like cornerbacks Adrian Colbert and Will Davis have experience playing safety and could make the move.

"Everyone could be a possibility and that's something we'll discuss, especially now when we find out what Tartt's issue is," coach Kyle Shanahan said. "As those numbers start growing, we could use more people."

James had a nice pass breakup against Aaron Burbridge in team drills and is working at both safety spots. Jerome has been something of a ball magnet with a couple of interceptions early in camp while he works mostly at free safety.

Other news, notes and observations from Monday:

-- Shanahan called Monday's practice the most "balanced" of this camp so far, which is to say that the offense and defense took turns getting the better of each other.

-- Quarterback Brian Hoyer continues to play well and he might have made his best throw as a Niner on Monday even if it wasn't a completion. Early in the session, Hoyer threw a perfect deep ball about 50 yards in the air to an open Aldrick Robinson near the goal line. Robinson couldn't come down with it but it was an impressive throw nonetheless. And Hoyer did a nice job of avoiding pressure from defensive tackle Earl Mitchell to get it off. Later, Hoyer climbed the pocket against pressure and threw another long touchdown pass to receiver Marquise Goodwin, who just continues to make big plays in this camp. Hoyer also threw a perfect deep dig route for a completion to Pierre Garcon and a nice deep ball to Garcon's outside shoulder in coverage, but cornerback Dontae Johnson came up with a pass breakup, one of his best plays of camp.

-- Speaking of Johnson, he and running back Carlos Hyde had a couple of physical exchanges. Hyde caught an out from Hoyer and threw a forearm shiver into Johnson's chin that jarred his helmet loose. A couple of plays later, Hyde ran off the right side only to find Johnson there waiting to deliver an impactful hit. It didn't escalate beyond that, and that's the type of physical football Shanahan probably likes to see. Johnson is getting a lot of work with the first-team defense as Keith Reaser recovers from a knee issue.

-- In one-on-one pass rush drills, the defensive line continues to win many of the matchups, except against left tackle Joe Staley. But Quinton Dial had success against center Daniel Kilgore, D.J. Jones knocked Tim Barnes to the ground after a nice spin move and Solomon Thomas also shoved Zane Beadles back into the quarterback with relative ease on an early rep. Of the Niners' three centers, Jeremy Zuttah seemed to hold up the best, faring much better against Dial than Kilgore did.

-- Linebacker Reuben Foster intercepted quarterback Nick Mullens again on Monday, a pick that had Shanahan more excited than either of the first two he's made in practice. Why? Well, as Shanahan explained it, Foster bit on the same play in Sunday's practice, learned from it then made the play on Monday for an interception. Foster has also been active against the run. It seems like it would be a good time to see Foster get bumped up to the second-team defense when practice resumes Wednesday. Even if he's going to make some mistakes, let him do it against guys of more comparable talent than what he's currently seeing.

-- Tight end George Kittle is dealing with a hamstring injury and didn't practice Monday. That opened up some opportunities for undrafted tight end Cole Hikutini. Hikutini had been highly touted as rookie free agents go but hadn't done much to this point of camp. He took advantage of his chances, with a handful of nice catches and a near miss on a contested pass in traffic.

-- C.J. Beathard got some run with the second-team offense early in practice though Matt Barkley was back in later on. Beathard had a much better day Monday after some struggles on Sunday. Barkley had a nice connection with Robinson for a touchdown on an out-and-up late in practice.

-- Defensive end Aaron Lynch can't be written off just yet. He is down to about 270 pounds and Shanahan lauded his efforts to come in in shape. It's paying off for Lynch, who had two potential sacks in team drills and came up with an interception off a deflection from Dial.

-- Right tackle Trent Brown bounced back with a solid day in which he allowed no obvious sacks after a rough day on Sunday. ... Undrafted linebacker Jimmie Gilbert suffered a torn ACL on Sunday and will miss the season. ... Wide receiver B.J. Johnson is dealing with tears in his hamstring and was waived/injured to make room for receiver Tim Patrick. The Niners claimed Patrick off waivers from Baltimore.

-- The 49ers are off on Tuesday and will return to work on Wednesday.