SANTA CLARA, Calif. -- The San Francisco 49ers put the finishing touches on their preseason and training camp Sunday with their exhibition finale.

The past month-plus has included plenty of intrigue in the Bay Area, most of it centered on the Niners' fascinating quarterback dynamic. Incumbent Jimmy Garoppolo and rookie Trey Lance competed "their ass off," according to coach Kyle Shanahan.

As we head toward the Sept. 12 opener against the Detroit Lions, let's answer some pressing questions on how everything has gone so far, what we know, what we think we know and what the future might hold for the 49ers at quarterback.

How did the 49ers use Garoppolo and Lance in camp and the preseason?

Pretty much exactly how Shanahan said they would at the start of camp. Garoppolo got the vast majority of the work with the starters while Lance worked with the backups. For the first few weeks of camp, Lance got the occasional rep with the starting offense but only for five snaps, all of which were designed running plays being installed into the offense specifically for Lance. That changed over the past week-plus as Lance worked with the starters for specialized situations, starting with an eight-play drive in a joint practice with the Chargers and then splitting reps with Garoppolo with the starting offense in move-the-ball periods and red zone work. Lance also got some time with the starting offense in preseason games, particularly the finale against the Las Vegas Raiders.

How did Garoppolo and Lance perform?

Both quarterbacks had their share of ups and downs throughout camp.

Garoppolo got off to a good start, hit some rough patches and then often found himself on mini hot streaks followed by some struggles. Interceptions remained an issue, as Garoppolo threw nine in the 19 practices open to media. But he also had moments where he was locked in and quickly distributing the ball all over the field, such as the Aug. 16 practice when he completed his final 10 passes, including a touchdown to receiver Mohamed Sanu in a move-the-ball period.

Lance didn't have as many turnovers, throwing only three practice interceptions, but he did have some of the accuracy issues that evaluators saw on his North Dakota State tape. When he missed, he often missed high, which increased the chances of a turnover, particularly when throwing over the middle. Lance also found himself under pressure a lot, which sometimes made it hard to get a read on his progress. Shanahan said some of that was protection related and some of it was on Lance to get the ball out quicker. Still, Lance was excellent in red zone drills, throwing eight touchdowns and running for at least three more. He showed a willingness to push the ball downfield, something he did with more success and regularity than Garoppolo.

The three preseason games didn't move the needle much. Garoppolo was 10-of-16 for 105 yards with an interception and a rushing touchdown. Lance played much more and finished 19-of-41 for 276 yards with three touchdowns, an interception and a rushing score.

Who is going to start at quarterback in Week 1?

Shanahan has so far declined multiple opportunities to make it official, but all signs still point to Garoppolo with Lance working in situationally, barring some sort of injury-driven change to the situation.

Why has Shanahan been hesitant to announce a starter?

Because, frankly, he doesn't have much reason to tip his hand. Shanahan made it clear before camp started that it would be tough for Lance to surpass Garoppolo. Lance getting more work with the starters left some wondering if it had turned into more of a competition than Shanahan let on. Though it's fair to view it that way, the bigger reason has been that Shanahan clearly plans on using Garoppolo and Lance in tandem in real games.

So, how will a QB tandem work, exactly?

Shanahan hasn't explicitly stated how it's going to look and how often Lance will rotate in, but he's been quite clear with the general outline. He cited what the New Orleans Saints did with Drew Brees and Taysom Hill as a blueprint. Obviously, Lance is a more polished passer, which leaves Shanahan more room for creativity in the passing game. The idea of rotating the quarterbacks to take advantage of Lance's running ability and arm strength seems like a good jumping-off point.

If nothing else, it gives opponents a lot to consider when constructing a game plan.

"When you do get a quarterback who does have a different skillset than your starter, regardless of whether they're ready to do a whole game ... I know that can really affect people," Shanahan said. "You have to prepare for that stuff a lot. Other defenses can't just go out and play against something that you haven't been preparing against."

How long before Lance becomes the starter?

Since there's no way to predict matters of health, we can't really use that as the basis to answer this question, other than to note Garoppolo has only started more than five consecutive games once in his career (2019). From a schedule standpoint, the Niners have two winnable road games to open the season (at Detroit and Philadelphia) before things get interesting against Green Bay, Seattle, Arizona, Indianapolis, Chicago, Arizona again and the Los Angeles Rams.

Starting Garoppolo and playing Lance situationally allows Lance to get some much-needed experience while also providing a bite-sized litmus tests on his state of readiness. If Lance can ace those opportunities, it would go a long way in applying pressure on Garoppolo. Much of this question will depend on how the team fares. So long as the Niners are winning and Garoppolo is doing well, there's little reason to believe Shanahan will stray from the current plan.