Thanks for the reply.
Well, the casing is not "cut" to house an optical, it has a copper mesh/grid/whatever in the area where the drive would be, so the physical size of the drive is irrelevant.
I just need to know if the connector is available (active) or not, and, if so, where can I find an adapter.
Since I have already upgraded to an ssd, I just need extra storage, so any hdd will do.
Edit: is there any reliable software that will show me available, even if unused ports?