Under the rules of the NBA CBA, a majority of players who sign free agent contracts in July are not eligible to be traded until Dec. 15 of the following season, which came on Sunday.
Teams like the Los Angeles Lakers have had around 25 games to evaluate their rosters, and now can begin making moves to improve, or go the opposite direction and sell to acquire assets leading up to the trade deadline on Feb. 6.
The Lakers, in particular, did not make many moves during the offseason so the Dec. 15 date more so affect players they are trying to acquire as opposed to their own.