Where is Trent Williams? Who is McCaffrey’s backup?

SANTA CLARA — Time for the 49ers’ first mailbag of training camp, and although submissions come in these days via social media, let’s dedicate this episode to my neighborhood’s retiring mailman, Harold:

When is the time to panic about the Trent Williams situation? (@BD49ers)

The season starts Sept. 9 against the New York Jets, late into that Monday afternoon (5:15 p.m.). This needs to be resolved much before then, however. It’s not that Williams vitally needs practice reps ahead of his 15th season. The starting offense needs his dominant presence to develop rhythm and momentum, because, right now, camp is not going great with Jaylon Moore and others auditioning at left tackle.

Unlike Brandon Aiyuk’s offseason filled with social-media posts about his contract angst, Williams laid low, showed up to watch the last practice of mandatory minicamp, then did not report last week to camp. Apparently he seeks to regain top-of-the-market status befitting the NFL’s three-time reigning All-Pro left tackle. The 49ers are cornered more by him than Aiyuk and must pay THE man.

How does the RB2 spot look? Feels like a crowded room. (@itsmerobertooo)

Jordan Mason is getting a shot at loosening Elijah Mitchell’s grip on the backup role behind NFL rushing champion Christian McCaffrey, whose workload is being minimized in training camp.

“Nothing against Elijah, there’s been no falloff in Elijah at all, but JP (Mason) runs at a very high level,” coach Kyle Shanahan said Monday, after Mason got first crack at RB1 reps with McCaffrey sitting out. “… (Mason) did a hell of a job for us last year. We’ll see how camp plays out. But I love both of those guys and got some depth behind them too.”

Those three, plus fullback Kyle Juszczyk, should stick on the roster. Patrick Taylor Jr. and undrafted rookie Cody Schrader are long shots. Then there is Isaac Guerendo, kind of. Guerendo’s hamstring injury in the first practice will sideline him for multiple weeks, casting doubt on him for preseason games. The initial 53-man roster is due Aug. 27.

Will Malik Mustapha battle for a starting spot? (@gabelb4)

Probably not this camp. Those starting safety roles are reserved for Ji’Ayir Brown and Talanoa Hufanga, if all goes well the next month or so with the latter’s comeback from ACL repair. George Odum, a special teams ace, has flourished with Brown as a first-string option, while Hufanga works his way off the Physically Unable To Perform list for a potential return next week in joint practices.

Mustapha impressed in down-field coverage earlier in camp, including on an interception. Known more for his physicality, his 5-foot-10 frame can make more noise now that pads and contact are permitted.

How do we get tickets for Saints-Niners shared practice in Irvine? (@JRitner)

You don’t. The Saints’ training camp at UC Irvine is reportedly the NFL’s only one fully closed to the public, even though the Rams opened their sessions at the same site in previous years.

The 49ers are slated to practice there Aug. 15-16, then they’ll return to host the Saints at Levi’s Stadium on Aug. 18 in the only game there this preseason. Those are the only joint practices the 49ers are holding; the Rams are conducting four of them, with the Chargers (twice), the Cowboys, and the Texans.

TE 2 has been an issue for years. Charlie Woerner was great on special teams, but not a threat on offense. Is Latu or Logan Thomas a viable option/upgrade? (@510maleake49er)

They have a month left to convince the 49ers if they are. Latu has had a slow start, though not as blatantly woeful as his rookie year’s camp. He caught Brandon Allen’s first pass of Monday’s team drills and quickly raced up field, so that’s a positive development. Thomas, known more for his receiving skills as a converted quarterback, threw a nice block to buy Josh Dobbs time on a completion to Mason Pline, a 6-foot-6 undrafted rookie who could steal a roster spot or at least stick on the practice squad. Not to be overlooked is Brayden Willis, who improved in the spring with first-team reps while George Kittle recovered from core-muscle surgery; Willis, however, couldn’t block out Deommondore Lenoir from making a sideline interception Monday.

Is Ricky Pearsall legit? (@jakejcrew)

He debuted at training camp Monday, at long last after a hamstring strain put him on the Non-Football Injury list when rookies reported two weeks ago. His hands and route running looked pro-ready in the spring, so now we get to watch him in pads, in contact drills, in preseason games before Year 1 begins. He doesn’t look as natural a punt returner as veteran Trent Taylor, who knows this offense from his 2017-2020 stint. Taylor, in fact, could be the opening-day returner and a WR3 or WR4. So far, Pearsall certainly looks capable of contributing as a rookie.

Are they gonna cut Tanner Mordecai? (@miliokiroga)

Two years ago, I thought there was no way the 49ers would keep a fourth-stringer in Brock Purdy. Good thing they did, eh? Mordecai has not attempted a pass in team drills through five practices at camp, and when he throws in warmups, his motion (to the untrained eye) involves calling upon every muscle in his body.

How has Ben Bartch and Chris Hubbard looked? (@zachudamann)

It’s looking like the end of the mailbag if we’re diving deep into backup offensive linemen. But seriously, Bartch served as the first-string center Monday while Jake Brendel got the practice off to rest his knee. Protection improved slightly across the board in camp once pads came on Monday. Better evaluations could come once one-on-one linemen drills take place.

What is Frank Gore’s roll with the team? (@soleil1127)

Gore, the 49ers’ all-time leading rusher, in his second year as a personnel advisor and was on the sidelines Monday watching practice. He retired after the 2020 season, so he has two more years before becoming eligible for the Pro Football Hall of Fame as the NFL’s No. 3 all-time leading rusher. (Disclaimer: Gore and tight end George Kittle each wrote a foreword for my upcoming book, The Franchise: San Francisco 49ers, that comes out Sept. 24.)