Soccer is unique to other sports in that there are usually a couple different competitions going on at once. You have your regular season, which leads to the playoffs and then the eventual champion. On top of that, you also have the US Open Cup. This is a tournament style competition that takes place during the season. Lastly, you have the CONCACAF Champions League, which is a competition between the best teams in the region.
This article provides a quick guide to the different competitions FC Dallas could possibly be playing in at any given time as well as hopefully clears up any confusion that might come up.