Can I move eSATA Drive into case without reformatting the drive?

I backed up files from one 1TB eSATA drive to another 1TB eSATA drive. It now occurs to me that it might have been better to have installed the backup drive in my computer case [less clutter on my desk].

Not wanting to do the backup all over again, can I simply install the drive in my computer without having to reformat the drive [and lose everything]?

Thanks in advance.

I wouldn't think you should encounter any problems by installing it in your case. After doing some searching I couldn't find anthing that says it won't work.Fabe