SANTA CLARA, Calif. – The San Francisco 49ers will be without two projected defensive starters for at least the next few weeks after free safety Jimmie Ward suffered a broken collarbone in Thursday’s organized team activity and defensive end Nick Bosa was diagnosed with a Grade 1 right hamstring strain.

The 49ers confirmed both injuries on Thursday with the likelihood that both players will miss the rest of the offseason program. The team hopes Bosa and Ward will be at full strength by the time training camp begins in late July.

Of the two injuries, Ward’s is the more serious as the recovery time from a fractured collarbone is expected to take between eight and 12 weeks. Bosa is expected to miss “the next few weeks.”

Network reported that Ward suffered his injury while diving for a ball during the team’s third OTA on Thursday. The broken collarbone is the latest in a lengthy injury history for Ward, who finished last season on injured reserve with a fractured forearm.

Ward has ended four of his five seasons on injured reserve, including a broken collarbone suffered in 2016. Despite Ward’s missing 29 of a possible 80 regular season games since he was a first-round pick in 2014, the 49ers re-signed him to a one-year, $4.5 million deal in March.

Bosa, whom the Niners drafted with the No. 2 overall pick in April, should be back to health sooner than Ward. While his injury will keep him out of the rest of the team’s OTAs, it could also prevent him from participating in the mandatory full-squad minicamp that’s scheduled for June 11-13. The start of that minicamp is exactly three weeks from when Bosa suffered the injury.

Although Grade 1 is considered the mildest of hamstring strains, the 49ers don’t intend to rush Bosa back, which means the aim will be to have him at full strength when training camp opens in July.

Bosa suffered the injury about halfway through the 49ers’ second OTA on Tuesday. Bosa participated in the first OTA on Monday and did individual drills and 2-on-2 pass-rush drills, but he shut it down for the day a couple of snaps into 11-on-11 work. He watched the rest of the practice from the sideline and was able to walk back to the locker room with a slight limp.

Immediately after Tuesday’s practice, coach acknowledged the hamstring injury but did not know the severity. Bosa’s participation in the offseason program comes on the heels of a final collegiate season at Ohio State in which he played in three games before suffering a core muscle injury on Sept. 15 against TCU.

That proved to be Bosa’s final college game, as he declared for the draft and began preparation for it soon after. Upon arrival in the Bay Area, Bosa was cleared to participate in the team’s rookie minicamp on May 3, but he did not do team drills that weekend as the Niners eased him in.

Bosa and Ward join an extensive list of Niners who aren’t taking part in OTAs because of injuries. That group includes starters or key contributors such as linebacker Fred Warner (knee), running back Matt Breida (pectoral), center Weston Richburg (knee, quadriceps), tight end Garrett Celek (concussion and back), running back Jerick McKinnon (ACL), linebacker Kwon Alexander (ACL) and cornerback Jason Verrett (Achilles). Quarterback Jimmy Garoppolo (ACL) is also working back from injury, though he’s participating in everything except team drills during OTAs.

The 49ers are expecting most of their injured players to be ready for the start of training camp.

“This is the most time I’ve had of people missing OTAs, but we’ve been really healthy the last two OTAs and it’s been the opposite at camp,” Shanahan said Tuesday. “Maybe it’ll be the opposite this year — we’re not healthy in OTAs, which is maybe a good sign for training camp. I know which one I’d rather have. We knew this going into this year. I mean, we knew we had, I think it’s 12 guys before this started that we knew wouldn’t be participating in OTAs. Then you’ve got your six new guys, too. Some things have come up, which is pretty normal, but when you stack that up, it is different with reps and things like that. Hopefully that’ll lead to a better training camp.”