Post­ing on the Don Mur­phy forums, Roberto Orci has con­firmed that nei­ther he nor Alex Kurtz­man will be return­ing for the third episode in the Trans­form­ers tril­ogy. Ehren Kruger (The Ring, Scream 3, Trans­form­ers Revenge of the Fallen) is tak­ing over from the pair.

So Bob and Alex is it true. you wont be involved this time round.
It’s true.

Sorry to hear that Roberto, really I am. Are we in good hands with Mr. Kruger? Does he know his Trans­form­ers?
He does. He really did his home­work. He’s awesome.