According to this Variety report, senior execs at Blizzard, Neversoft and Infinity Ward have all been signed into the newly-formed Activision Blizzard on five-year contracts. From the piece:
CEO Bobby Kotick confirmed for me that the top folks at Blizzard have all signed new five year deals. “We realized it would be impossible to compete [with ‘World of Warcraft’] and so ultimately my only issue was making sure they were committed for at least five years. They are committed to the franchise in a way we rarely see, since it’s something they created from scratch and is their life and livelihood. It didn’t take a lot to get them to make that commitment.”
More through the link.