If the drive is in a foreign status (and/or "missing"), then it is already "offline" ... you simply need to remove it and replace it with the new one.  ALWAYS replace hot-swap drives "hot", then make sure drivers and firmware are up to date once the rebuild completes and the system is healthy (start with iDRAC and BIOS, then the other system firmware).
Hi Experts We are getting following errors in OpenManage for RAID 10. There are 8 hard disks and one of them is creating this problem. It is blinking green and amber. A foreign configuration has been detected.: Controller 0 (PERC H710 Mini) The current firmware version 21.1.0-0007 is older than the required firmware version 21.2.0-0007 for a controller of model 0x1F38: Controller 0 (PERC H710 Mini) Virtual disk degraded: Virtual Disk 0 (Virtual Disk 00) Controller 0 (PERC H710 Mini) Predictive Failure reported: Physical Disk 0:1:5 Controller 0, Connector 0 Controller event log: PD missing: SasAddr=0x5000c500437c0025, ArrayRef=2, RowIndex=0x1, EnclPd=0x20, Slot=5. : Controller 0 (PERC H710 Mini)  Storage Service Controller event log: Predictive failure: PD 05(e0x20/s5): Controller 0 (PERC H710 Mini)  Seeing the errors, we have purchased new HDD and need your advice how we should proceed? Should we take off line the old hard disk and then hot plug the new HDD? or we just need to upgrade the firmware for raid controller?   
Virtual Disk Degraded and Predictive Failure Messages