Megan Fox Going Downhill?

So I guess it's official...Megan Fox has been replaced in The Transformers franchise by this chick:

My sources say she's Rosie Huntington-Whiteley, a Victoria's Secret model.  By "sources" I mean a half-assed Google search.

So does this mean Megan Fox has jumped the shark, so to speak?  Don't get me wrong, I'm a big fan, but it seems she's been on a slide for a while.  I had high hopes for her in Diablo Cody's "Jennifer's Body", but after bad reviews, I haven't even given it a look.  She'll be in DC's upcoming "Jonah Hex", but even with a strong cast (Josh Brolin, John Malkovich), I'm already having my doubts about that one. 

Just some random thoughts.  So what do you think?  Is Megan Fox's career in trouble?