When you say you "turn on your Slingplayer to watch NHL cames", it suggests to me that you are saying that you disconnect the power from your Slingbox while you are not watching it. I believe it is best to leave your Slingbox turned on (i.e., have it powered up) all the time, whether you are watching it or not.
As I understand the procedure with my SlingPlayer software on my Windows PC, when I log in to my Slingbox account on the Slingplayer window, the software checks the database of addresses that Slingbox HQ maintains for all activated Slingboxes to see what Wide Area Network IP address and what Local Area Network address are recorded in its database for the Slingbox registered to your login ID. If either of those addresses have changed since they were lasted updated in that database at Slingbox HQ, the Slingplayer may not be able to find your Slingbox to display its signal.
How can this happen? (1) Your Internet Service Provider assigns a unique "Wide Area Network" IP address to your cable modem. If their system goes down for a rather long time, then it is possible that when service is restored, a different IP address will get assigned to your cable modem. Typically, the ISP assigns a specific WAN IP address to your router for a specific length of time (typically, a few days) and when that time is done, the connection to your cable modem is automatically renewed by your ISP using the same WAN IP address. But if the service in your entire neighborhood/city is disrupted for a long time, the WAN IP addresses could be assigned differently when the service is restored.
(2) If your router assigns a different LOCAL Area Network IP address to your Slingbox, then the Slingbox address directory could also get out of sync with the actual address that your Slingbox is currently using. This can happen anytime your home has a power outage for any extended length of time. When the router reboots, it assigns a new (and possibly different) LAN IP address to each device in your house that connects to the router. For most computers, this is not a problem, as they are usually happy to work with any IP address. But, I believe, once your Slingbox gets its first local IP address the first time it is setup in your home, it would like to keep that address forever.
I don't have a solution to problem (1), other than to keep your cable modem turned on all the time and hope your ISP doesn't have major outage problems.
For problem (2), you can insure that your router always assigns the same LAN IP address to it by having the router assign a static IP address to your Slingbox, rather than have the router use the (normally default) approach of assigning a dynamic IP address to the router. See the users manual for your router on how to do this. Once you have the static IP address assigned, it is also wise to program the router the forward the port needed by the Slingbox for some of its communications to that static IP address. In my case, the desired port is 5001 (don't know if this is common to all Slingboxes), and the user manual for my router told me how to do this. Some of the responses to other questions in this forum also point to a website that can automatically configure your router to do the port forwarding.
Power cycle both the router and the Slingbox after making these changes, and hopefully you will be good to go.
Once I did the static IP address assignment and port forwarding on the router to which my Slingbox is connected, all of my connection problems went away, and I have had fine connectivity both via the web and via the SlingPlayer software since. AND, the "support" tab on slingbox.com shows when I log in to my account what the WAN and LAN IP addresses are for my Slingbox, and when the last connection update was made.
Good luck. I know this is a long response, but hopefully it will help you.