There’s a new coach, general manager and starting quarterback for the 49ers in 2017, as well as numerous new veterans and rookies on a roster that needed a talent overhaul following a disastrous 2016 campaign.

So, as the 49ers begin training camp – pointed toward the season-opening game Sept. 10 vs. the Carolina Panthers – there are far more uncertainties than certainties.

Over the next six weeks or so, a number of Niners’ starting roles must be determined. Plus, we don’t yet know how new franchise leaders will evolve. These are the five biggest questions facing the 49ers in training camp:

Will Kyle Shanahan have what it takes to be a head coach?

There’s a long list of former offensive and defensive coordinators who flopped as head coaches. Shanahan seemingly has what it takes to make the step up from longtime offensive coordinator duties to be a head coach. But, until he’s faced with overseeing an entire team, working with general manager John Lynch, solving conflicts and problems, instituting new systems and making in-game decisions and adjustments, we won’t know. One thing is sure: the 49ers need some stability at head coach following the Chip Kelly and Jim Tomsula eras.

Can Brian Hoyer be an effective quarterback for this team?

After being led by Colin Kaepernick and Blaine Gabbert the past two seasons, the 49ers are getting a fresh start with veterans Hoyer, Matt Barkley and rookie C.J. Beathard taking snaps this summer. Hoyer has shown in all of his stops around the NFL that he can be a solid passer and leader as a starter. Yet, he’s viewed as a stopgap until the 49ers can bring in a frontline veteran or draft choice in 2018. With a strong 2017, Hoyer – who already knows Shanahan’s system and has the confidence of his head coach – could show he’s good enough to start next year, too, which would give San Francisco even more time to build overall strength at other positions until a franchise quarterback is acquired.

Which veteran will start at center?

Will it be holdover Daniel Kilgore or offseason pick-up Jeremy Zuttah at center in Game 1? When healthy, Kilgore has played well for the 49ers. Zuttah, a former Raven who made the Pro Bowl in 2016, was acquired to challenge him. What happens at center could impact the rest of the offensive line. Both Kilgore and Zuttah have played guard, too, so one could swing into the left or right guard spot to compete with Zane Beadles or Josh Garnett.

How will this defense work?

The 49ers will transition from a 3-4 front to a 4-3 front, but one based on the fluid, shifting system used in Seattle and Jacksonville. It will include a strong safety playing close to the line of scrimmage for better run support and a free safety capable of covering a large chunk of real estate on the back end. Coordinator Robert Saleh is in charge of putting the right players in the right positions to flourish, so look for a lot of experimenting and testing in summer practices and games to find the right combinations.

Will Carlos Hyde and Vance McDonald stay?

Lynch has brought in plenty of competition at running back and tight end this offseason, and the thinking by some 49ers watchers has been that Hyde and McDonald could be vulnerable. Each is young and talented, but Hyde has fought injuries and McDonald hasn’t made the impact as a receiver that some expected. It’s possible that one or both could be traded before Game 1, opening up opportunities in the backfield for Tim Hightower, Joe Williams, Matt Breida and Kapri Bibbs, or at tight end for rookies George Kittle and Cole Hikutini to join Garrett Celek and Logan Paulson.