"Missing Disk" from Array

Hello All

My Unraid is currently reporting that a HDD is missing however its available to mount in unassigned drives. when I add it back to the array it says that everything on the drive will be lost which I would like to avoid. before I start manually moving the data off the drive and back in to the array is there a way to have unraid recognise that the dive is there and that it can mount it in to the array without wiping it?

Many thanks