Desmond Mason is coming back to Oklahoma City. In a three-team trade expected to be announced later tonight, Oklahoma City will acquire Mason from the Milwaukee Bucks and veteran forward Joe Smith from the Cleveland Cavaliers, according to NBA sources. Oklahoma City will send point guard Luke Ridnour and Adrian Griffin to Milwaukee. To complete the deal, Milwaukee will send point guard Mo Williams to Cleveland. The Cavs are also sending Damon Jones to the Bucks. Mason, the former Oklahoma State standout who played in Oklahoma City from 2005-07 as a member of the temporarily-displaced New Orleans Hornets from 2005-07, has career averages of 12.5 points, 4.5 rebounds and 1.7 assists. Mason, who will turn 31 in October, averaged 9.7 points, 4.3 rebounds and 2.1 assists in 59 games last year with the Bucks. Smith, the No. 1 overall pick in 1995, is entering his 14 NBA season. He has career averages of 11.9 points, 6.9 rebounds, 1.1 assists and 0.9 blocked shots. He averaged 10.1 points and 5.2 rebounds last year in Cleveland and Chicago, where he played 50 games before his mid-season trade to the Cavs. Both Smith and Mason have expiring contracts, which will give Oklahoma City more salary cap space next summer. Mason would have been a part of a logjam at forward in Milwaukee after the Bucks traded for Richard Jefferson this summer and drafted West Virginia’s Joe Alexander in June. Ridnour faced the same playing time quandary with Oklahoma City after it drafted Russell Westbrook and returnd veteran Earl Watson. Ridnour has two years remaining on his contract at $13 million. The deal will free up more minutes for Westbrook, who showed flashes of his potential as the franchise’s point guard of the future in the Orlando Pro Summer League. Mason and Smith also add veteran players to a young Oklahoma City roster. Both players are regarded as hard-nosed defenders and locker room leaders. Mason and Smith are also versatile players who can play and defend multiple positions, which is expected to add more flexibility to coach P.J. Carlesimo’s rotation.