Jon Daniels says that the Rangers are "looking into" signing Colby Lewis, who is planning on returning to the United States after two impressive seasons of pitching for the Hiroshima Carp in the Japanese League.
My guess is that Lewis would be brought in on a minor league deal with a spring training invite and a relatively early opt-out date, with the idea being that he could provide some insurance and depth in the spring for the pitching staff and possibly go to Oklahoma for a month or so and pitch in the rotation there if need be.
T.R. Sullivan has a story up with quotes from Daniels about Riley Cooper, saying that the organization has been in regular contact with Cooper's agents, and that the team expects Cooper to report in March.