The Giants failed to make the playoffs in Buster Posey’s first season as president of baseball operations, then kicked off their offseason on Monday by firing manager Bob Melvin. The firing of Melvin marks a third consecutive year that the franchise has replaced a prominent figure. … You, without a doubt, hope there can be consistency in these leadership positions.”The changes likely won’t stop with Melvin. At full strength, the Giants’ bullpen featured Rodríguez, Doval, Tyler Rogers, Erik Miller and Ryan Walker. And speaking of Adames, he’s more than willing to help recruit if it means bringing more talent to the Bay.