Expectations for the 49ers couldn't be higher as they enter the preseason in Year 2 of the Jim Harbaugh era. It's Super Bowl or bust.

With arguably the NFL's best defense returning intact, along with a retooled offense, there's no to reason to believe this year's team won't be better than last year, when it was a play or two away from reaching the Super Bowl.

Questions to be answered in exhibition season:

How much better can QB Alex Smith be with the addition of WRs Randy Moss, Mario Manningham, A.J. Jenkins and RB LaMichael James? It might not be answered in the preseason, but Smith now has the weapons in place that should allow OC Greg Roman to take a less conservative approach with his play-calling duties. Smith tied an NFL record with just 5 INTs last season, and the team's plus-28 turnover differential was as big a reason for its success as any. RB Frank Gore could end up the biggest beneficiary of the offseason additions; opposing teams now will have to account for the additional options.

How will the secondary respond to defending 50-plus passes a game? By the time the playoffs rolled around last year, it was clear that running against the 49ers was not a viable option. The result? The Saints and Giants averaged 60.5 pass attempts per game in the postseason compared to just 36.2 pass attempts against the 49ers during the regular season. Yes, it's a small sample size and the Giants and Saints both pass above the league average, but that trend will likely continue during the regular season when the 49ers match up against QBs Aaron Rodgers, Matthew Stafford, Eli Manning, Drew Brees and Tom Brady. They'll be a lot of pressure on the secondary and pass rush.

Is QB Colin Kaepernick a viable No. 2? The jury is still out on 2011 second-round pick Colin Kaepernick. His dreadful preseason last year (23.9 passer rating) can be forgiven, but if he doesn't show marked improvement, Josh Johnson will be in line to step in. Both players have struggled with accuracy in training camp, so it'll be interesting to see how they perform in the preseason.

Follow 49ers reporter Kyle Bonagura on Twitter: @CBSSportsNFLSF and @KyleBonagura

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