The Rangers have signed former Major League left-hander Nate Robertson to a Minor League contract with an invitation to Spring Training. He was signed after a tryout in front of Rangers scout Mike Grouse and Minor League pitching coach Brad Holman. Robertson, 35, hasn't pitched in the Majors since spending 2010 with the Marlins and Phillies, going 6-8 with a 5.95 ERA in 18 starts and three relief appearances. He was with the Tigers from 2003-09, and has a career record of 57-77 with a 5.01 ERA in 187 starts and 36 relief appearances. Most of Robertson's time in the Majors has been spent as a starter, but he will likely compete for a spot in the bullpen as a reliever.