Mitchell has struggled to recover from knee surgery he had in the offseason and has not played at all this season. He had five goals and 19 assists in 76 games in the Kings' Stanley Cup-winning 2011-12 season and was plus-20.
On Monday, the Kings acquired defenseman Robyn Regehr from the Buffalo Sabres for the Kings' second-round picks in the 2014 and 2015 drafts.
After making an acquisition Monday, the Kings traded away Davis Drewiske. Los Angeles picked up a fifth-round selection from the Montreal Canadiens for the defenseman.
Drewiske, 28, played in 20 games with the Kings this season, recording four points, 14 penalty minutes and a plus-3 rating. Drewiske was originally signed by the Kings as a free agent on April 1, 2008, and played in 126 NHL games total.