A friend of mine brought over his PlayStation 4 copy of Need For Speed: Rivals today and I was really into it. I'm thinking about purchasing the game digitally, but I'm curious - will purchasing the digital version enable me to access the current install, or will I need to download another copy of the game?

Having trouble finding an answer to this elsewhere

I bet you do. When you have the disk, you still need the disk to authenticate, which brings up the assumption parts of the game are still on the disk. The digital download will end up installing everything, including the authentication.

My guess would be no. It's probably a slightly different file that needs to confirm a disc is in the system but I would say, since you're going to buy it anyway, or at least thinking about it, just try it out and see what happens. Worst case scenario, you just have to delete the disc install and download the game.

I saw a tweet from a Sony person that I'll never be able to find, but it said people with slow connections could rent a disc to install and it would work with their digital purchase.

That'd be pretty awesome if you could.

Jeff mentioned being unable to do that with Injustice, I'd assume that holds true for the rest of the catalog. I wouldn't be surprised if you couldn't, since on PS3 even save files were incompatible between versions. I was hoping they'd fix all that stuff, but it sounds like they might not have.

Ah yeah, I must've read that tweet wrong. On this PS Blog FAQ they say you have to delete the disc install and fully download the digital version.

I hope they patch this out later. So it's just a small download instead, like on the XboxOne.