Roster Analysis: San Francisco 49ers

Here is a close look at the San Francisco 49ers as they head into their season opener against the Green Bay Packers Sunday, 1 p.m.(ET)

UNIT BY UNIT ANALYSIS:

QUARTERBACKS: Starter -- Colin Kaepernick. Backups -- Colt McCoy, B.J. Daniels.

All eyes will be on Kaepernick after he burst onto the scene in 2012, ripping the starting job away from Alex Smith. Does he take a step forward or have opposing defenses played catch up? If he goes down, McCoy steps in -- at least early in the season. Daniels showed to be a talent with an impressive preseason, which forced the team to use a spot on its 53-man roster to keep him. Stashing him on the practice squad was not an option.

RUNNING BACKS: Starters -- RB Frank Gore, FB Bruce Miller. Backups -- RB Kendall Hunter, RB LaMichael James, RB Anthony Dixon.

Old reliable Gore keep adding miles on his odometer, but has shown no signs of drop off the past few years. With a talented duo of Hunter and James behind him, Gore should see between 14-18 carries a game. Hunter's season-ending Achilles tear showed no last effects in the preseason and he'll be counted to play a key role -- especially as James works his way back from an MCL sprain.

TIGHT ENDS: Starter -- Vernon Davis. Backups -- Vance McDonald, Garrett Celek, Chris Harper.

Davis is expected to be the team's No. 1 target with the injury to Michael Crabtree. The team said goodbye to Delanie Walker in the offseason and welcomed McDonald through the draft. He played a lot of receiver in college and will be an instant upgrade as a receiving option over Walker, who left for a big pay day in Tennessee. Celek made the team last year as an undrafted rookie and fended of MarQueis Gray in training camp to remain with the team. Harper was drafted as wide receiver by Seattle, picked up off waivers and moved to tight end.

WIDE RECEIVERS: Starters -- Anquan Boldin, Kyle Williams. Backups -- Jon Baldwin, Quinton Patton, Marlon Moore.

Boldin figures to be the top option among receivers, but Patton, a fourth-round pick, was the talk of the end of the preseason. His touchdown receptions in the final two games were reason for optimism just days after the organization ridded itself of former first-round pick A.J. Jenkins, who was swapped for Baldwin. Baldwin disappointed in Kansas City, but has more upside in terms of physical gifts than Jenkins did. Williams had solid chemistry with Kaepernick before his season ended with a knee injury a year ago.

OFFENSIVE LINEMEN: Starters -- LT Joe Staley, LG Mike Iupati, C Jonathan Goodwin, RG Alex Boone, RT Anthony Davis. Backups -- G/C Daniel Kilgore, G Joe Looney, OL Adam Snyder.

The NFL's top line returns all five starters and added Snyder, who started at RG two years ago. It's an athletic, physical unit that opens up lanes for Gore and gives Kaepernick time to throw. Every member on the line is a potential Pro Bowl selection.

DEFENSIVE LINEMEN: Starters -- DLE Ray McDonald, NT Ian Williams, DRE Justin Smith. Backups -- DT Glenn Dorsey, DT Tony Jerod-Eddie, DE Demarcus Dobbs (suspended), DE Will Tukuafu.

Possibly the least impressive unit on the team, despite being anchored by Smith. Williams won the starting job over Dorsey with a strong camp, but they'll likely both see significant time. McDonald is solid, yet unspectacular and good against the run.

LINEBACKERS: Starters -- LOLB Ahmad Brooks, ILB Patrick Willis, ILB Navorro Bowman, ROLB Aldon Smith. Backups -- Corey Lemonier, Nick Moody, Dan Skuta, Nate Stupar, Michael Wilhoite.

Quick, who is the best linebacker on the 49ers? That answer is debatable and also might be the answer to the question: Who is the best linebacker in the NFL? Willis is the popular answer, but internally Bowman is viewed by some as a better overall player. Meanwhile, Smith was voted team MVP and Brooks was second-team All-Pro.

DEFENSIVE BACKS: Starters -- LCB Carlos Rogers, RCB Tarell Brown, NB Nnamdi Asomugha, SS Donte Whitner, FS Eric Reid. Backups -- Craig Dahl, C.J. Spillman, Raymond Ventrone, Perrish Cox.

Gone is Dashon Golson and in is the first-round pick, Reid, out of LSU. The team also added Asomugha and appears to have more depth than a year ago, despite the loss of Goldson and an ACL tear to CB Chris Culliver. If the secondary plays well, the defense will be fine. If it struggles, there could be some uses. See: Super Bowl.

SPECIAL TEAMS: K Phil Dawson, P Andy Lee, LS Kevin McDermott, KOR Kyle Williams, PR Williams.

Dawson was the most accurate kicker in the NFL last year among those who had at least 20 attempts. He nailed 29-of-31 kicks, which would be a significant upgrade over David Akers, the NFL's second-least accurate kicker from a year ago (29-of-42). Kicking at Candlestick Park isn't easy, but it's hard to do worse than Akers. Lee's an all-time great and McDermott replaces 13-year veteran Brian Jenkins, who was beloved by the fan base. Williams will likely handle return duties with LaMichae James sidelined for the first few weeks.