Here's another workaround that does allow you to play online:
1. (With Internet connection Enabled) On the XMB, go to Account Management, press the Triangle button, and select Sign Out.
2. Boot the game.
3. Progress to the Main menu (where the title used to hang).
4. Wait for the loading bar to complete and the PRESS START BUTTON prompt to appear.
5. Press the PS button and Sign In to your PSN account via the XMB overlay.
6. Press the PS button again to return to the game.
I tried loading my PSN copy of NFL Blitz, the issue was never updated or fixed.
PlayStation 3 Slim - 500 GB
Game froze at loading screen, I tried formatting the hard drive and re-downloading and installing no luck still froze at loading title screen.
I paid for this game, it wasn't free for me...