"Dario came out of the game in Boston with soreness in the elbow," said manager Jeff Banister on Sunday. "He's made some progress, but we just felt like it was an opportunity to let it continue to calm down, get it treatment."
In 13 appearances for Texas this season, Alvarez holds a 3.48 ERA with 12 strikeouts in 10 1/3 innings.
Adding Robinson to the roster gives the Rangers some added positional flexibility as the 28-year-old has played all three outfield positions with Triple-A Round Rock over the past two seasons. He also has the ability to play first, second and third base on the infield if needed.
At the plate, Robinson has posted a .264 average for Round Rock with 14 doubles and an OPS of .790.
This move also corresponds with left-fielder Delino DeShields getting a day off on Sunday. Banister described DeShields as "sore", but added that the off-day was part of his regular schedule.
Texas could gain some further roster clarity on Monday, when the team is expected to evaluate third baseman Adrian Beltre. Following three games in extended spring training, Beltre flew back to Texas, where he is resting on Sunday, before a decision is made on his potential return from a calf injury.
Keegan Matheson is a reporter for MLB.com based in Toronto. This story was not subject to the approval of Major League Baseball or its clubs.