SANTA CLARA, Calif. -- Jim Harbaugh is always good for supplying a vivid verbal painting.

The San Francisco 49ers’ unconventional fourth-year coach was in rare form as the team opened camp July 24. Harbaugh’s theme for the start of camp was “rebirth.” He enthusiastically went into great detail of what he was feeling as the 49ers assembled to kick off the season.

"It's the start of the new year in football. It's like it's your own birthday,” Harbaugh said with zeal only he can exude. “Like it's a family reunion. It's like a rebirth. Feel like you come out of the womb and [are] reborn into football. … It's such a positive happening, that first day. Imagine you're kind of in the comfort of the offseason, like being in the comfort of the womb. You get plenty to eat in there, it's warm, very cozy. And then you're born, into somewhat of the unknown. A lot of people looking at you, lot of faces looking at you, lot of excitement. It's light, it's bright, it's noisy, it's the crazy world of football. Again, it's a real happening. Wish everybody could experience it."

As Harbaugh and his team moved headfirst into the season, in many ways the feeling is more about completing a mission than starting one.

The 49ers have been to three NFC title games and one Super Bowl under Harbaugh. This training camp is designed to be the beginning of ending that mission with a Super Bowl crown. Anything less would be failure.

THREE REASONS FOR OPTIMISM

Colin Kaepernick should benefit from having a deep group of 49ers receivers this season. AP Photo/Nick Wass Passing game: At no point last season did the 49ers’ aerial attack look as strong as it has during this training camp. Actually, it’s stunning to see how much better this area is than it was last season. Quarterback Colin Kaepernick is surely benefiting. A few examples: As a rookie, Quinton Patton was the No. 3 receiver last year. This year, he’s improved, but he might be the sixth and final receiver on the 53-man roster. Jonathan Baldwin was a frontline receiver for a spell in 2013. This year, he was cut 10 days into training camp. The additions of veterans Stevie Johnson, Brandon Lloyd and explosive fourth-round pick Bruce Ellington to go with holdover starters Michael Crabtree and Anquan Boldin make for a pretty special group. It has showed in camp. Deep roster: General manager Trent Baalke said three days into camp the 49ers had about four or five openings on their 53-man roster. Imagine that -- an NFL team knowing up to 49 of its regular-season players six weeks before the start of the season. That wasn’t hyperbole by Baalke. Take a gander at this roster. It is stacked. Almost every position is full of plus players. There is little weakness on this team, and it has shown in the level of competition in camp. The 49ers have been feisty. Kaepernick said it’s because there is so much talent, and the intensity level is heightened because people are fighting for just a few jobs. The rookies: The 49ers are poised to get immediate help from some rookies. Their first-round pick, defensive back Jimmie Ward; second-round pick, running back Carlos Hyde; third-round picks, linebacker Chris Borland and center Marcus Martin; and fourth-round picks, Ellington and cornerback Dontae Johnson, have all been factors in camp. All of them can be contributors in the regular season. That is a major shot of youth for a veteran-stacked team.

THREE REASONS FOR PESSIMISM

Injuries: Yes, the 49ers are deep, and they need to be. They have gotten knocked around in what has been a physical camp. Running back Kendall Hunter (torn ACL) was lost for the season, and running back LaMichael James (dislocated elbow) was lost for the preseason in the first weekend of camp. A week later, standout nose tackle Glenn Dorsey was lost for the majority, if not all, of the season with a torn biceps. The defense was already working from behind with inside linebacker NaVorro Bowman set to miss about half of the season as he recovers from an ACL tear. The good news for the 49ers is they are deep at their injury spots, but trouble could be brewing if the rash of injuries continues. Flux on offensive line: The 49ers’ offensive line has been an NFL gold standard. That has not been the case in training camp. Guard Alex Boone is holding out, and there doesn’t appear to be an end in sight. Joe Looney has taken his place at right guard. Looney has been decent in camp, but he was overpowered at Baltimore in the first preseason game. Next to him is Jonathan Martin, who has had a rough go at right tackle. He is playing for Anthony Davis, who is out until Week 1 as he recovers from offseason shoulder surgery. At center, Daniel Kilgore is a first-time starter. All the change has been reflective in camp. Backup QB plan: Here’s the bottom line: Kaepernick better not go down. Blaine Gabbert is who he is. He has had his moments in camp, but when the lights of the preseason came on, he struggled badly. But Gabbert is essentially guaranteed to be on the roster because he is getting paid $2 million. Gabbert, acquired in March in a trade with Jacksonville, can still improve under Harbaugh and his staff. But if he continues to struggle, the confidence level in him will be low.

OBSERVATION DECK