This season has been similar. The Giants have been decimated by injuries, in particular those to the pitching staff (4 of 5 starters ended up on the DL (disabled list) for a good part of the season) and to position players such as Hunter Pence and Joe Panik (Pence missed over half of the season, and Panik missed 34 games between August 1st and September 6th). Other starters that have spent time on the disabled list include Angel Pagan, Nori Aoki, Andrew Susac, Hector Sanchez, and Gregor Blanco. The Giants have had a hard time staying healthy this season. That's why they probably won't make the playoffs, not because they're lacking in talent, and why they shouldn't panik.
The upside is that because of the injuries, they've been able to cultivate a lot of new talent that should pay dividends in the future. Matt Duffy has shined at 3rd base and is in the running for Rookie of the Year (Pablo Who?), Chris Heston has shown promise as a staring pitcher (he threw a no-hitter this year), and Kelby Tomlinson (aka, Clark Kent) has a good chance of becoming a regular next year -- probably not at 2nd base (assuming Joe Panik is healthy), but as a utility infielder/outfielder. Even Gregor Blanco appears to have come into his own, which may prove key if Angel Pagan continues to struggle with injuries.
That doesn't mean the Giants should do nothing in the offseason. Although they have a two or three top pitching prospects in their minor league system, they still need to bolster their pitching staff. Lincecum may be done as a Giant (although he's enticing as a reliever), Tim Hudson is retiring, and it's hard to know if Matt Cain will make it back. Thus, they should try to hold on to Mike Leake and pick up at least one more starting pitcher. Jake Peavey can give them 5-6 good innings, but that's what you want from a 4th or 5th starter, not your number two or three. With luck Cain will rediscover his old magic or at least some of it, and who knows maybe the Giants will make another deep run into the playoffs in 2016. It will be an even year, after all.