49ers injury notes: Isaac Guerendo setback; Nick Bosa, George Kittle updates; Mac Jones doesn't throw

San Francisco 49ers head coach Kyle Shanahan spoke with reporters on Thursday and provided several key injury updates as the team continued organized team activities (OTAs), which began on Wednesday.

Isaac Guerendo suffers offseason setback

It was already expected to be a competitive battle for touches in the 49ers' running back room in 2026. Now, second-year running back Isaac Guerendo faces another obstacle after suffering an offseason injury setback.

"Guerendo tore his [pectoral] lifting (weights) about a month ago," Shanahan said.

The coach added, "It's not a season-ender, but it's right around the end of training camp."

Veteran running back Christian McCaffrey shared his thoughts on Guerendo's injury while praising the young player's mindset during recovery.

"Sometimes, this game is super unfortunate," McCaffrey said. "He was working his butt off all offseason, and sometimes it's that freak stuff that happens, where you strain something training in the weight room or something. It's unfortunate, but he's got the best attitude. He's coming in every single day with a smile, still working just as hard, and it's not a season-ending injury.

"He'll be back, so it's also perspective. As much as he's down, he knows that he will be back for the season, so I think there's also some enthusiasm there."

Updates on Nick Bosa, Keion White, and Mykel Williams

Shanahan was also asked about the recovery progress of defensive linemen Nick Bosa, Keion White, and Mykel Williams. Bosa and Williams are working their way back from ACL injuries suffered last season, while White underwent ankle surgery after suffering a gunshot injury.

"They're coming along," Shanahan said. "They're all in their rehab with a number of other guys. A couple of those guys will have a chance at training camp, and we'll see with Mykel as it goes."

Speaking with reporters, Bosa admitted the recovery process has been lengthy but said he is encouraged by his progress.

"I'm pretty far along," Bosa said. "I'm out on the field doing a lot of stuff, trying to just take it slow because I tend to push things quicker. Obviously, I got injured pretty early last year, so there's plenty of time for me to really kind of lay the groundwork to be ready for a long season.

"So, yeah, it's going really well, and I plan on being ready."

George Kittle progressing well

Tight end George Kittle has repeatedly stated that his goal is to be ready when the 49ers open the regular season against the Los Angeles Rams in Melbourne, Australia. Kittle is recovering from a torn Achilles suffered during San Francisco's playoff victory over the Philadelphia Eagles.

Shanahan sounded optimistic about the veteran tight end's recovery.

"He's on track and very positive and happy every day, like Kittle is, and doing good," Shanahan said. "Kittle works his tail off, and he's extremely talented and gifted, so he'll do it as fast as he can."

Why Mac Jones didn't throw at practice

Mac Jones received a pay raise from the 49ers, and many expected to see Brock Purdy's primary backup participate during Thursday's practice. However, Jones did not throw during the session.

According to Shanahan, the decision was precautionary.

"His shoulder was a little sore today," Shanahan explained. "He said he could have gone through it, but it was unnecessary, and it gave a chance for other guys to get more reps."