Henrique de Castro, head of Google's global Partner Business Solutions Group, will join Yahoo at chief operating officer in January. It appears that Yahoo CEO Marissa Mayer is indeed using her former employer as a recruiting ground, as many had expected. De Castro's loss is a blow for Google but a notable win for Yahoo, and he didn't come cheap. Mayer offered him a $56 million pay package, according to All Things Digital. He'll be worth it if his experience in operations, strategy, partner management and revenue generation helps her turn the perpetually struggling Internet company around. Yahoo says De Castro will oversee strategic and operational management of Yahoo sales, operations, media and business development efforts worldwide. He'll report to Mayer.