Alex Boone's contract could be a long storyline for the San Francisco 49ers this summer.The 49ers start training camp practices next week. Boone is not expected to report without a new contract.Unlike fellow minicamp holdout, star tight end Vernon Davis, Boone appears bent on staying away until he gets a new deal. Davis recently said it wouldn't be the "end of the world" if his holdout doesn't result in a new deal. Both Boone and Davis have two more seasons remaining on their contracts.