Bolt - one internal sata port or two?

I understand I can replace the existing HD in the bolt to increase capacity. I also know there is the esata port on the back that can be used additionally to the internal HD with an "approved" external HD.

My question is "Is there a second empty sata port inside?" If so, could I keep the original drive and add a second one using the internal sata port, understanding that I would have to route the cable out of the box to the drive since there is no room inside?

Thanks.