Odd sound at engine start

[blkxer]

Recently, my 03' X5 4.4i (85k miles) started to have a strange sound on startup. It does not happen all the time. It seems to happen more when I start the car after it's been parked for some time. The sound is a bit hard to explain, but as the engine is starting, there is horrible sound that happens along with the usual engine startup. It's only there for quick second and goes away as soon as the engine is started/idling. The best description I can make of the sound is that it sounds like metallic/sandpaper rubbing or scratching noise.

Anyone know what this might be? I'm guessing that the starter may be the culprit, that it may be going bad soon? Want to bring it to my mechanic, but it doesn't happen 100% of the time on startup.

Trying to record the sound the next time it happens so I can post it.