Ok so here's what I know...
I heard it from someone I trust. That's all I can say. This person isn't working on the game and could be wrong. I trust that it isn't wrong.
They are likely scrambling to pick a new PS+ game to deliver some good news with the bad and announce it then.
I will likely get banned (temporary, I hope?!?) if I'm wrong so I guess that will let you know how confident I am.
As for personal opinion: Motorstorm was my favorite racing series last gen. I love Evolution. When there was a rumor about a delay last time I posted that I hoped it was true
because I want the best possible game from them. I don't need it at launch. I take the jim sterling approach to launches.
.. give me good games spread out, not rushed games all piled on day one.
That said... it's a disaster for Sony PR. This + Watchdogs is bad for next gen sales in general this year. It just further cements the feeling that the systems aren't ready. Which is true. Modern systems never are. The 3DS shipped without an Eshop, the vita didn't have PSone support, the Wii U OS was a disaster. There will be similar growing pains for microsoft and Sony. We already know a lot of stuff has been pushed from launch (youtube uploads, usb storage, ID @ xbox, etc for x1, gaikai, certain headphones working, hdcp being turned off, etc for Ps4). There will also be games for both systems that once you play them you will wish they were delayed. I did make a post a few months back about lowering launch expectations.
If i'm wrong, I'll see ya when I'm allowed back. But I don't think I'm wrong. I would assume if it's untrue someone at sony/evo will crush it shortly. If it's silent... well, wait for the announcement of "hey _____ is on ps+ on day one and also driveclub is delayed but who cares because ______ is on PS+ on day one!."