To qualify for a sign-and-trade, all of the following must be true:
The player must re-sign with his prior team -- a team cannot include another team's free agent in a sign-and-trade.
The player must finish the preceding season with that team (deals are no longer allowed that sign-and-trade players who are out of the league, such as the sign-and-trade that sent Keith Van Horn from Dallas to New Jersey as part of the Jason Kidd trade in 2008). The player cannot be a restricted free agent who has signed an offer sheet with another team (see question number 43).
Starting in 2013-14, the team receiving the player cannot be above the "apron" ($4 million above the tax level) after the trade1.
Starting in 2013-14, the team cannot receive a player in a sign-and-trade if they have used the Taxpayer Mid-Level exception (see question number 25) that season.
The trade must be completed prior to the first game of the regular season (sign-and-trades are not allowed once the season begins).
The player cannot be signed using the Non-Taxpayer Mid-Level exception, the Taxpayer Mid-Level exception, or any exception that cannot be used to offer a three-year contract (see question number 25).