The right-handed Lewis, 30, was pitching in Japan the last two seasons. He was 11-9 with a 2.96 ERA in 176 innings pitched in 2009 with Hiroshima Carp. Lewis had 186 strikeouts and just 19 walks. He had similar numbers in 2008, going 15-8 with a 2.68 ERA in 178 innings of work.
General manager Jon Daniels didn't comment on Lewis but said the club was "open to adding a starter." The Rangers would need to drop someone from the 40-man roster before signing Lewis.
Lewis, who was with the Rangers for parts of three seasons, will join a pool of pitchers vying for a spot in the rotation. The club continues to look at other starting possibilities as well.
A source said the Rangers will have a representative on hand when Ben Sheets throws for clubs Tuesday at the University of Louisiana-Monroe. Sheets, a free agent, is coming off flexor tendon surgery on his right elbow. Sheets had a two-year deal worked out with the Rangers last offseason, but it fell through after Sheets' physical showed he needed surgery.