Phillips was designated for assignment when the Rangers needed to open up a 40 man roster spot when Scott Feldman was activated from the 60 day disabled list.
Green, an infielder, is not on the 40 man roster, and will go to Round Rock, where he will provide middle infield depth for the organization.
Phillips was a 23rd round draft pick in the 2004 draft, and is currently on his second option. He had a 4.43 in 44 2/3 innings pitched for Round Rock this season.
Green, meanwhile, has spent time in the majors with Boston, the Yankees, Toronto, Tampa Bay, Atlanta, Seattle, and the Dodgers.