Not likely. Many have asked and nothing has changed. They don't seem to care about their users on any platform. Your best bet is to downgrade your slingbox firmware to where the video isn't encrypted and use an older version of slingplayer that might run in wine. Otherwise theres a vlc plugin to watch slingbox floating around somewhere. Basically you have no good options available. At the very least the could make a plugin for linux which would probably take a day since its just firefox.
There is no official way to run SlingPlayer on Linux, but there are a number of unofficial ways to do it.
I recommend you look at this, it works relatively well.
Or if you prefer the older version of SlingPlayer
The last alternative is to install something like VirtualBox and run Windows within Linux. Then you could follow the officially supported Windows SlingPlayer setup.
If you want help on Linux, I suggest creating a thread over on placeshiftingenthusiasts.com -- there seem to be people willing to help with unsupported and/or advanced setups over there, things that Sling Media is unable to assist with.
Ok. So an update here for Linux desktops. I have a solution! I stumbled upon this completely by accident and haven't tested it yet because some compiling and patching is involved. If you would like to know the solution, please PM me or message me as I do not think this should be public just yet. For one reason, it's quite beta. Secondly, it's not officially supported by SlingMedia, who seem to not care if a Linux version is ever created.