Here are the five biggest questions for the 49ers heading into training camp:

1. Which young wide receiver will emerge?

When Michael Crabtree tore an Achilles in May, coach Jim Harbaugh vowed that a young receiver would step up opposite Anquan Boldin. A.J. Jenkins, Ricardo Lockette and Quinton Patton became top candidates, and now Kyle Williams will join the mix after his knee rehabilitation.

2. Which cornerbacks will stay?

Veterans Nnamdi Asomugha and Eric Wright will attempt to crack a unit that has all five cornerbacks from last season. Carlos Rogers could face the stiffest challenge, thanks mainly to his $5.5 million in base salary and shaky play last season. Chris Culliver played well as the No. 3 cornerback in the regular season but had a dismal Super Bowl week.

3. Is Eric Reid fast-tracked to start at safety?

The 49ers hoped to offset Dashon Goldson's free agency exit by moving up in the first round to draft LSU safety Eric Reid. To claim that starting job, Reid must make impact plays and announce his presence, all while competing against veterans Craig Dahl, C.J. Spillman and Darcel McBath.

4. How does Colin Kaepernick lead the offense?

Rather than keep Alex Smith to back up Colin Kaepernick, the 49ers are counting on a combination of Colt McCoy, Scott Tolzien and/or rookie B.J. Daniels. Kaepernick has only 10 career starts, so this camp will be key to help him get more comfortable, both as a leader and playmaker. Now is the time to test out that seemingly unlimited playbook.

5. Who complements the defensive line?

While Glenn Dorsey joins Justin Smith and Ray McDonald on the defensive front, auditions are underway for the backups, including Lamar Divens, whose off-field incident with Ahmad Brooks could make for awkward times. Ian Williams is a virtual lock while Demarcus Dobbs and Will Tukuafu could be challenged by Tony Jerod-Eddie and draft picks Tank Carradine and Quinton Dial.