Fox left the franchise and her role as Mikaela Banes before the third film after falling out with director Michael Bay and was replaced by British model Rosie Huntington-Whiteley.
LaBeouf told MTV News that he asked Transformers director Michael Bay to consider going in a different direction when choosing Fox's replacement but was turned down in favour of Huntington-Whiteley, who was better suited to a summer blockbuster.
"I remember pitching to Mike, 'Maybe we should go with a more bookish type'," he recalled. "Mike said to me - and there's two faces to this that are hilarious and insane and also genius, so three sides.
"I remember him saying to me, 'Shia, we're not going with any bookish anything. This is a summer movie - we need a summer girl'. To his credit, Mike really understands his audience. There's a certain audience that goes to see these movies that has certain requirements that it needs out of its summer movies."
LaBeouf recently described Fox's axing as a "blessing" as it allowed his character Sam Witwicky to develop a better story arc.
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Watch Digital Spy's interview with Transformers: Dark of the Moon star Rosie Huntington-Whiteley and executive producer/director Michael Bay below: