The Rangers were going to acquire Robertson regardless, as they were looking for an outfielder with speed after Jim Adduci went on the DL with a broken left pinky finger.
Robertson, a 5-foot-8 right-handed hitter, has never played in the Major Leagues. He is a career .304 hitter in seven Minor League seasons, with a .381 on-base percentage and a .411 slugging percentage. He also has 131 career stolen bases.
"He's got some speed and he can play all three outfield positions," Rangers manager Ron Washington said. "I can use him to pinch-run."
"We view him as a winning type of offensive player," assistant general manager Thad Levine said. "He's a very patient hitter and a scrappy performer. He fits the way [Washington] wants the game played and what he demands from his players."
Robertson could also serve as the Rangers' leadoff hitter if Choo ends up on the DL with a sprained left ankle. Robertson was a 33rd-round Draft pick by the Padres in 2008 out of Oregon State University. He has spent the past three seasons in Triple-A.
"This is every kid's dream," Robertson said. "You don't know how you are going to feel. It really hasn't sunk in yet. I'm sure it will sink in when my cleats hit the dirt."
Robertson was with Triple-A El Paso in Las Vegas when he got the call from Padres farm director Randy Smith. He was told it was good news and bad news.
"I said, 'OK, hit me with whichever one you want first,'" Robertson said. "He said, 'The bad news is we traded you to the Rangers.' I thought that wasn't so bad, I like Round Rock. Then he said, 'The good news is you're going right to the big leagues.'"
T.R. Sullivan is a reporter for MLB.com. Read his blog, Postcards from Elysian Fields, and follow him on Twitter @Sullivan_Ranger. This story was not subject to the approval of Major League Baseball or its clubs.