Your team can also play friendly matches. These matches are just meant for extra experience, for trying out new tactics or simply to see who of your friends is the best manager.
At the end of each season, the teams that don't participate in league playoffs will automatically be given a number of friendly matches. You can also play friendlies by challenging your friends through the "my matches" page, or any other team when you go to the page of that team.
Each player can get experience in his first 6 friendlies each season. For each of these matches he'll get 150 experience points.
The counter for friendlies is not reset at the end of the season, but a little earlier when the league playoffs start so the scheduled friendlies at the end of the season use the new season's match counter.