Rapper turned actor Tyrese Gibson has been spouting off about possibilities for Transformers 4 to Movieweb:

"There are no concepts, no direction, no nothing for Transfomers 4, because everyone has been so focused on Transformers: Dark of the Moon. But here is the safety net. Are you ready for this? Michael Bay decides to not come back for Transfomers 4. There is always Steven Spielberg! I am not saying that Steven Spielberg is for a fact going to direct Transfomers 4. But it is a beautiful safety net to know that one of the biggest, most respected directors in the world happens to be an executive producer on Transformers. He is someone who knows this world. And he could easily step in and direct Transfomers 4 if he decided to."

So what you're saying is is if Steven Spielberg decided he wanted to direct the fourth instalment of a franchise he made happen he could? Someone give that man a can of coke...