The San Francisco 49ers are particularly deep at linebacker and cornerback this year. Who makes the squad at those positions, and could the team make a trade at one of those spots?We dive into those offseason nitty-gritty questions in this week’s mailbag. Thanks for all the great queries, which, as usual, have been lightly edited for length and clarity.Which rookie was most impressive in the OTAs, and will they have a positive impact on this season? — Russ W.First, an admission: Because the 49ers scuttled their mandatory minicamp, reporters watched only two spring practices. Two! So I don’t feel nearly as insightful about the spring season as I have in previous years.Having said that, it was interesting to see Jaden Dugger line up as the strongside linebacker. He got that opportunity because the regular strongside ‘backer, Luke Gifford, got a concussion when he collided with Mike Evans (yikes!) early in OTAs.I don’t know if Dugger ultimately lands that job this season. After all, he’s a fifth-round pick who spent just one college season as an off-the-ball linebacker. Still, he has traits — length, size, smarts — that translate well to the position, and he has the backing of new linebackers coach K.J. Wright.Receiver De’Zhaun Stribling and running back Kaelon Black flashed in at least one of the practices I watched, and I’ve heard coaches liked what they saw from cornerback Ephesians Prysock. The linemen? As always, we have to wait until the pads come on in training camp to assess that group.Which 49ers rookies have the best chance of starting?Matt BarrowsIt seems that in many years, an undrafted rookie makes the final 53-man roster, from Kendrick Bourne a decade ago to Jordan Mason to your guy Evan Anderson. Who’s your way-too-early prediction for having the best shot this year? — Ben E.There are a few candidates. I’d handicap it like this:• P Jack Bouwmeester. He’d just have to beat out one competitor, Corliss Waitman, to be the 49ers’ punter this year. Of course, he has to join the squad first. Bouwmeester, an Aussie, is waiting for his work visa to be approved.• TE Khalil Dinkins. If George Kittle (Achilles) begins the season on the physically unable to perform list, there’d be an opening for a third tight end after Luke Farrell and Jake Tonges. Dinkins, a blocking specialist, would have to beat out Brayden Willis for that role.• Fifth DT. The first four defensive tackle spots will likely go to Osa Odighizuwa, Alfred Collins, C.J. West and Gracen Halton. The fifth? Bryson Eason and James Thompson Jr. have a shot at leapfrogging Anderson and Sebastian Valdez for that spot.• DE Mikail Kamara. Will Mykel Williams (ACL) be ready for Week 1? If not, the 49ers would go into the season with Nick Bosa, Keion White and Romello Height at defensive end. That would leave two spots among Sam Okuayinonu, Cam Sample, Kamara and others.Do you think the 49ers are done at safety? — Paul B.That’s my guess. The 49ers simply don’t put a great deal of value on the safety spot, which is ironic for a team whose general manager is a Hall of Fame safety. The earliest the current regime has drafted a true safety is the late third round — Ji’Ayir Brown in 2023. (Tarvarius Moore was also a third-rounder in 2018, but the 49ers thought they could make him into a cornerback when they drafted him.)My sense is they believe they can find the right mix among Brown, Malik Mustapha, Marques Sigle and Ashtyn Davis. And if they can’t, or if there are injuries, there are always quality safeties looking for work. For example, Harrison Smith, Donovan Wilson, Taylor Rapp, George Odom and Jamal Adams are among the veterans currently available.You mentioned using the safeties in a dime package earlier this week, but the league has been trending toward big nickel (Seattle, Nick Emmanwori). Can you see Raheem Morris going with a big nickel package to get all three young safeties out there at the same time? They did a little last year with Jason Pinnock. — Clay J.Yes, for sure. In fact, Sigle seems especially cut out for that role, given he was a hybrid nickel player at Kansas State. (He played just about everywhere in the defensive backfield.) He’s not nearly as big as Emmanwori, who’s a little over 6 feet 3, weighs 220 pounds and has a 6-6 wingspan. Sigle is 5-11, 200 pounds. Still, he’s fast and fluid and not afraid to stick his nose into action at the line of scrimmage.Most likely trade candidate during/end of the preseason? — Danny S.Renardo Green? There have been persistent trade rumors — albeit denied by the 49ers — dating back to last season. The team has some depth at cornerback after signing Nate Hobbs and Jack Jones in free agency and drafting Prysock in the fourth round. If Green were traded, there might be a four-way battle for the starting spot among Hobbs, Jones, Prysock and Darrell Luter Jr.Why haven’t the 49ers extended Jake Brendel yet? They have no clear heir apparent behind him at center. — Andrew H.I agree there’s no clear heir. Brett Toth, 29, will be the backup there this season, but he’s signed only through this season. I also have a sneaking suspicion that they’ll give draft pick Carver Willis a look there at some point. He seems to have the disposition of a center. He reminds me of Eric Heitmann. Maybe they don’t expect a big market for Brendel, who turns 34 on the day they open the season in Australia.How do you view Jordan James? Last year, Kyle Shanahan gushed over James and again to start OTAs. With talk of giving CMC more rest during the season, does James have the traits to be a lead RB? — Kevin K.Yes, if Christian McCaffrey had to miss a game, my guess is James would start. I think he’s the most complete tailback on the roster after McCaffrey in that he can break off big gains, catch the ball out of the backfield, etc.Would he get McCaffrey-like touches? (I’m sure some fantasy football managers are curious about that.) No, I don’t think so. In a CMC-less scenario, Black likely would be regularly rotated in behind James.I see the linebacker room loaded with talent and special teamers. They normally carry 5-6 on the 53-man roster. Who do you think makes it this time? —Andy T.Fred Warner’s middle linebacker spot and Dre Greenlaw’s weakside spot are every-down positions, so you need quality backups at both. That likely points to Tatum Bethune (middle) and Nick Martin (weakside), who was coming on as a special teamer when he was hurt last season.I think the 49ers will hold onto Dugger. Heck, he could even be a Week 1 starter depending on which formation the Los Angeles Rams are in to start the game. He also seems like someone with the potential to excel on special teams.That leaves one spot for a proven special teams ace. Gifford was a Pro Bowler there last season, so he gets the nod for now. However, Garret Wallow looked sharp on coverage units when he arrived late last season and was playing middle linebacker in the spring with Warner and Bethune out. He’s a high-energy guy who’s a dark horse to make the team.Practice squad candidates include Wallow, Jalen Graham and Larry Worth III, whom Wright mentioned during a coaches’ availability earlier this month.How long will the 49ers hold on to Brandon Aiyuk? — John B.Through Week 6 (Commanders at 49ers)? I don’t think the 49ers are interested in letting him go — for free — to a team that’s not only in the NFC but that they face this season. Which is to say, not only is there no incentive to release him (unless Aiyuk applies for reinstatement from the reserve/left squad list to force the team’s hand), but there’s a disincentive to do so.Matt, if you could give John Lynch and Kyle Shanahan truth serum, what is the one question you would ask them separately nearly a decade into their time with the Niners? — Christoffer A.What really went down in the run-up to the Trey Lance draft?Who is going to win the World Cup? — Lino A.FIFA