The San Francisco 49ers had a terrific—and surprising—season this past year. Not only did they win 13 games and win the NFC West, but they made it all the way to the Super Bowl.

Heck, they even had a 10-point lead over the Kansas City Chiefs in the second half before blowing it.

As a result of their success a year ago, the 49ers are considered one of the favorites to represent the NFC in the Super Bowl yet again next winter.

But will there be problems in the Bay?

Here are the three biggest questions for San Francisco going into 2020:

3. How will the defense absorb the loss of DeForest Buckner?

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The Niners traded stud defensive lineman DeForest Buckner to the Indianapolis Colts for a first-round draft pick earlier this offseason, a move they basically had to make due to salary cap constraints.

But will their defense be able to handle such a huge loss?

Make no mistake about it: Buckner was a key cog in the success of the 49ers' defense this past season. He racked up 62 tackles, 7.5 sacks, a pair of forced fumbles, four fumble recoveries and a defensive touchdown. Alongside of Arik Armstead, he helped comprise one of the most dominant one-two punches in the NFL.

San Francisco took Javon Kinlaw with the 14th overall pick to replace Buckner, but Kinlaw certainly has some big shoes to fill.

2. Which wide receiver will step up?

Kyle Shanahan, Lamar Jackson, 49ers

The 49ers bolstered their receiving corps midway through this past season by swinging a trade for Emmanuel Sanders, but now, Sanders is gone.

That leaves a rather big hole behind Deebo Samuel for the No. 2 receiver spot, and it's a hole that one of the club's young wide outs will have to step up and fill.

Will that be Dante Pettis, who was a major disappointment in 2019? Could that guy be Kendrick Bourne, who came on during the second half and put forth a decent showing in the playoffs? Or maybe it will be Jalen Hurd, the Niners' third-round pick from a year ago who missed all of this past season due to injury?

Whoever it may be, someone has to step in and serve as a reliable target for Jimmy Garoppolo, because right now, outside of Samuel and tight end George Kittle, Garoppolo doesn't have a ton of weapons.

1. Will Jimmy Garoppolo improve?

On the surface, Garoppolo's numbers in his first full season as the 49ers' starting quarterback don't look bad at all.

He threw for 3,978 yards, 27 touchdowns and 13 interceptions while completing 69.1 percent of his passes and posting a passer rating of 102. One might even go as far to say that those are Pro Bowl-caliber stats.

But stats don't always tell the story.

It became blatantly obvious in the postseason that San Francisco leaned much more in its ground game than it did on Garoppolo's arm, and it really makes you wonder how much trust Shanahan has in his signal-caller.

Here is the thing with Garoppolo: he is already 28, so it's not like he has such a long road ahead of him for improvement. He needs to start getting better now.

Again, to be fair, he is somewhat limited in terms of weapons, but that doesn't change the fact that Garoppolo will be under the microscope next season.