If the disk itself is degraded, but the array (Virtual Disk) is not showing degraded, then your disk has been flagged with what is called a "predicted failure".  The disk likely has the green and amber lights alternating.  Your disk is failing, but has not yet failed completely or gone offline. Procedure: Force the disk offline or use the Prepare to Remove option for the disk. Replace disk with one of equal or greater size. A rebuild will probably begin automatically, but if it doesn't, you can start a rebuild manually by assigning it as a hot-spare (if it is in a 'Ready' state).
i have an Array Disk 0:0 that says it is degraded on a RAID 5 array.  The strange thing is if i go up one level in the server manager to the Virtual Disks it has the status checked green for Virtual Disk 0.  So is my RAID 5 degraded or what?  Also to initiate a rebuild wht is the best option?  Should insert a new drive or should i  pull out that one and insert it back.  Thanks.
Dell PE 2650 perc 4/DC Array Disk 0:0 degraded