Bad idea since USB3 storage with Linux could be best described as worst choice possible due to a lot of reliability issues popping up.
You didn't say which OMV version you're using (matters since different OMV versions reference drives by different means). When disks are referenced by label be prepared that the label might change depending on the USB enclosure in question so from OMV's point of view the disk is another one after attaching it via USB. Some USB-to-SATA bridges also 'eat' the last one or two sectors so the disk might not even be of same size afterwards.
Better look for a 2 port eSATA card based on ASM1061 or ASM1062 chipset combined with a separately powered eSATA enclosure. No hassles then since the drive is still accessible via SATA and from OMV's view nothing has changed.
Edit: only now realized that you're moving an already existing USB disk enclosure from an USB2 port to an USB3 port. Still opting for eSATA is the better idea.
Hey thank you for the input. Sorry for late reply. I never did do that but when I do I will go the eSATA route. Thanks.