If you are having trouble connecting to your opponent, such as freezing at the loading screen, not being able to select your team, etc, make sure both teams have the latest roster update downloaded. I don't know why but it makes a difference even though it doesn't affect the rosters in our online franchise.
To download the latest roster update, join an online match (not online franchsie), and it will tell you if your roster is out of date, then you will be prompted to download it.