Target: Johan Santana, LHP
2013 stats: Did not play due to injury
Santana is trying to return after missing last season following a surgery to repair an injured shoulder. In 2012 with the New York Mets, Santana put up a 4.85 ERA following a missed 2011 season with the same injury. In 2010, he put up a 2.98 ERA in 29 starts. He's a two-time Cy Young Award winner with the Minnesota Twins and could be one of the best changeup artists in the history of pitching.
He's still at a decent age (only 34) and seemingly has a pretty fresh arm, but injuries have obviously been an issue for him in the past. On one hand, you'd hate to bring him in if you're the Rangers when you're already hoping for an injury reclamation from Colby Lewis, but on the other, if the price is right, it certainly couldn't hurt.