Phillips, 34, is under contract for $27 million over the next two years. He hit .294 with 12 homers in 2015 for Cincinnati.
If the second baseman were to accept a trade, it would reunite him with manager Dusty Baker, who led the Reds from 2008-13.
Phillips was a three-time All-Star and four-time National League Gold Glove Award winner while playing for Baker.
William Boor is a reporter for MLB.com. Follow him on Twitter at @wboor. This story was not subject to the approval of Major League Baseball or its clubs.