I think you can export the virtual machine as ovf/ova from your workstation and import it to the ESXi. Keep in mind that ESXi 5 support virtual machine hardware version up to 8, if you created the VM in workstation with higher version of VM hardware I am afraid that there is no option to downgrade it. If this is the case the options are to upgrade the ESXi to an appropriate version so it supports the virtual machine hardware level, or to make P2V migration (vcenter converter standalone has a proxy mode now, this could be helpful in the case that the workstation and the ESXi are in different networks)
Inside Workstation use "change virtual hardware" from the menu VM -> Manage
Create a full clone with appropriate virtual hardware.
When that is done use commandline-tool vmware-vdiskmanager to convert the existing vmdk of the newly created clone to esxi-compatible format.
Adjust the vmx-file so that the esxi-vmdk is referenced.
Optional compress the vmx + vmdk with tar / gzip.
Upload the archive or vmx+vmdk to the ESXi into a new directory.
Register the vmx with Datastorebrowser.