In the middle of what has been a stale season so far in San Francisco, fans were given a reason to perk up a bit with the news that the team's prospect, first baseman Bryce Eldridge, was being called up to the Major Leagues. However, he won't be riding in on a white horse to save the day on a team that's currently 13-21; he'll be there to prove that he belongs. Coincidentally, 'proof' seems to be a word on the mind of team broadcaster Mike Krukow, as well. The former Giants pitcher turned mic man says that Edridge's call-up is likely much more than just getting a closer look at the 6'7" slugger. Instead, it's meant to let everyone on the MLB roster know that they are replaceable if things don't improve. “I don’t think anybody is safe right now,” Krukow commented during a Monday morning appearance on  KNBR’s “Murph & Markus”  show, following the disastrous road trip. “I really don’t.…