Can I swap a My Book Drive into a Mac Mini as a supplemental storage drive?

[nealj]

Hi, I recently purchased a Mac Mini (500gb 2011 model) as well as a Western Digitial My Book for Mac (1tb)

(Item model number: WDBAAG0010HCH-NESN) that I have used as the time-machine backup as well as the home to my music files and eyeTV recordings.

Unfortunately, this external drive has failed, and WD is sending me a replacement drive. 

However, I had planned to upgrade the Mac Mini by replaceing the startup disc with and 120gb SSD disk, as well as adding a second drive for additional internal storage. (Western Digital Scorpio Blue WD10JPVT 1TB 5400 RPM 8MB Cache 2.5" SATA 3.0Gb/s Internal Notebook Hard Drive -Bare Drive)

The WD tech who issued me the RMA, told me it was OK to open up the broken drive to try and swap the external drive into another external unit to try and recover the data, and after watching a video on how to do that, I was wondering if I could actually just use the drive from the My Book as the supplemental storage drive inside the mac mini?

I would grade my knowledge and ability on these matters as low to profficient, aside from upgrading the RAM in the Mini on my own, I'll be calling in a friend to help with the Mac Mini upgrade, so if anyone has any feedback on my above question, please feel free to use layman terms. 

And thanks!

[Vadir]

The internal drive for the My Book is a 3.5" drive, AFAIK the Mac Mini supports 2.5" drives.  Also you may confirm that your system can handle a 1 TB drive.