Selling a Team

When teams are sold, the CPU will take over and all players on the team will have their contract set to expire on day 40 of the current season. GM's on the team, and possibly long time players, will be allowed to take over the team if the owner wants to quit, to encourage continuity. Contact support to make it happen.
Players on the now CPU team will be able to be offered contracts just like if they were D-League teams, and will be replaced by CPU players when they do get moved. These CPU players will generally lose, but put up enough of a fight to not lose by 200 points.
If the team is broken when it's sold, it will get some cash to make sure it can pay salaries for the rest of the season.
At the end of the season, all these teams will be dropped to the bottom tier of the league and empty spots will be filled in by promotions from the tiers below. According to Bort, the exact rules of promotion are about 90% decided, but it will basically be the teams that made the playoffs, starting with the teams that lost in the conference finals, moving down, and comparing season records, points differential, etc.
Once the teams have been dropped, they will be resold with reset stadiums, fan support, cash, and a full CPU roster.
Teams are only sold during the offseason.