Roku would be the way to go, but you can also go with a $35 chromecast. With a Chromecast, you use the Sling TV or WatchESPN app on aSmart Phone/Tablet, then hit the Cast button in the app. Works really well.
Also, you can use your Sling TV username/password to log into WatchESPN so you can watch the SEC Network+ (Plus) games. SEC Network+ games are internet only
http://www.secsports.com/video/12255289/sec-network-sec-network-+-watchespn