Keep in mind that due to injuries that caused both missed games and limited opportunities in games, Frank Gore has only exceeded 300 carries once in his career. The guy is an absolute warrior and one of the toughest guys around, but his missed games don't tell the whole story. He has had multiple surgeries (both knees, both shoulders, fractured hip, etc.) that should concern any franchise. Also, look at his carry totals. There's a pretty clear trend and it;s not pretty.
2006: 312
2007: 260
2008: 240
2009: 229
2010: 203
If it was up to me, I'd make the niners give him a huge bonus just for making the them even remotely watchable for the last six years. He's such an easy guy to root for and he's been the heart and soul of the offense. But, the NFL is a business and contracts don't reward for what you have done in the past Rather, it's about what you will do in the present and future. He might have a decent year or two left, but unless it's an incentive laden contract, he's not getting a big payday at this point.