They didn't. Aronofsky is indeed directing Machine Man, but it's the Max Berry version. The less fun version. Berry's take comes from an online book he wrote, which he released one page per day. The full story will be released in the Spring of next year. Machine Man is the story of a tech geek who decides to replace his human parts with titanium performance upgrades.
The script will be handled by Mark Heyman, who also wrote Aronofsky's upcoming flick, Black Swan.
Since the screenplay isn't yet set in stone, this shouldn't have any effect on Aronofsky's involvement with Wolverine 2. Then again Fox still hasn't confirmed he'll be directing it. Fortunately we have the talkative Hugh Jackman already confirming that for us.
