User blog comment:Damac1214/Call of Duty 2014, codenamed "Blacksmith", set for reveal in May/@comment-11106160-20140430183658/@comment-1187559-20140430195222

The main tools of a Blacksmith is a Hammer and Anvil. Given the company is called "Sledgehammer" that likely has more to do with it. Besides, crafting has been in Zombies and Extinction now, you couldn't really make it become the main feature worth naming the project after.