First off, You are going to need a couple programs


Firefox 
Foxy Proxy 

I also recommend getting

Google Chrome


Download and install both Firefox and Foxy Proxy.

If you are already using Firefox. Fire it up and press Cltrl+Shift+Del including cookes but not saved passwords is not necessary. 

Now you are going to need a Proxy for Foxy Proxy. Get one from here

You might have to try a few till you find one that works but I have had best luck with ones that end in Port 3128

In Firefox go to Tools->Foxy Proxy->Options->


Click on Add New Proxy

You can put the name as anything
Click on the Proxy Details tab
Than click on Manual Proxy
The host name is (ie. 92.51.145.217 Port: 3128) put what ever proxy you got off the list

After that close out  Now go back up to Tools->Foxy Proxy->Use Proxy 92.51.145.217 for all URLS
Go to here 

Click on the Cardinals game MLB.TV basic feed


Now this might be going slow and you might have to try to reload it a couple times but eventually it will pass the Blackout check. Put in your login info. Let the video feed actually start. As soon as it starts going back up to Tools->Foxy Proxy-> Completely Disable FoxyProxy

That is it. It should work now. I also recommend using Google Chrome or IE while using MLB.tv sometimes using Firefox while broadcasting can mess things up. It is just another precaution but not entirely necessary.

P.S

If the Proxy ever stops working just get a new one.