If your standalone cablemodem is hooked up to the Time Capsule WAN port, and configured as DHCP as it should be, there is no double NAT situation.
Double NAT would only exist only if you had two routers in-line with each other, for example if your cablemodem was one of those all-in-one SMC or Cisco modems that Rogers sells/rents. And even then, those units can be configured in "Bridge Mode" to bypass the routing features.
If you purchased a modem from TekSavvy, then it's not an all in one, and a standalone unit which would not cause you double NAT issues if wired to your time capsule.
F**K THE NHL. Go Blue Jays 2013!!!