I would recommend you see if you can get the USB port replaced Vs scraping the drive just to recover the one 2 TB drive. Remember! Once you break the RAID 0 pair the other drives data is lost!
So first off I have not opened this drive. As such we just don't know how the drives are connected together and if they have a SATA interface.
So for argument-sake lets say the drive its self is a standard 2.5" drive so what Seagate drive would that be?? Here's the most probable candidate: 2.5" SATA Hard Drive #STBD2000102. We can see the height of this drive is 9.5mm across all of the drives. So from a size perspective the drive would fit your system.
BUT we still have a problem here! This drive is not workable in many of the 13" MacBook Pro's.
If we review the OWC - Data Doubler sheet we can see the 2012 13" MacBook Pro (MacBookPro9,1) has a compatibility note at the bottom that SATA III (6.0 Gb/s) drives have issues within the optical bay. This is not OWC failing but Apples! As they mis-clock the PCH chip.
While the Seagate we've assumed is the one being used in your external drive, has auto SATA port sense there is no means to lock it down to the slower SATA II (3.0 Gb/s) speed your MacBook Pro needs in the optical bay, so you do run the risk of data corruption. In addition, to that the optical drive carrier does not offer HD crash guard protection unlike the HD SATA port.
Again for argument-sake lets say you still want to give it a go. You would still need to reformat the drive to GUID and Mac OS Extended (Journaled). You really wouldn't want NTFS as you loose the meta information of the Mac file system.
I think this is not worth the effort given the loss of you're external which is repairable!
In addition, this is not really the ideal drive. I would go with just replacing my current HD for either a SSHD like the Seagate FireCuda or if you can swing it go full out with a Samsung 850 EVO both offer 2 TB drives (leaving the optical bay alone)