Consider Wesley Matthews due to be traded. Matthews hits every check as a trade candidate: a smart player at a young enough age (31) to still contribute but too old to wait for his struggling team (Dallas) to rebuild, and he has a marketable skill (38.5% from three this season) and good size (6’5″) at the guard position.
With younger options Seth Curry, Yogi Ferrell, and now Dennis Smith Jr. at guard for Dallas. The Mavericks would be best off turning Matthews into another young asset for their future, or a bad contract with draft picks attached. Matthews would be best off playing for a contending team like his old Blazers teams when he averaged as much as 16.4 points per game in 2013-14.