The trade was first reported by Bob Nightengale of USA Today.
The Rangers will get right-handed pitchers Josh Lindblom and Lisalverto Bonilla, according to reports.
Young had a five-year, $80 million deal with the Rangers through the 2013 season and a full no-trade clause, which he had to waive for the deal to go through.
The Rangers are picking up approximately $10 million of Young's remaining salary and the Phillies are giving him a no-trade clause.
Young will likely play third base for the Phillies. It's possible that he would not have had an everyday role for Texas in 2013.
Young, 36, is a seven-time All-Star and won the American League batting title in 2005 with the Rangers.