Hamburger, 25, was optioned to Triple-A Tucson. At Triple-A Round Rock in 2012, Hamburger made 21 appearances, going 0-2 with a 6.55 ERA in 45 1/3 innings. He threw eight innings in relief appearances for the Rangers in 2011, giving up four runs.
The Rangers designated Hamburger for assignment on June 22 to clear a spot on the 40-man roster for Roy Oswalt.
Hermida, 28, has been on the 15-day disabled list since April 28 (retroactive to April 27) with a strained left abductor. He has missed 53 games so far.
Hermida will still start a Minor League rehabilitation stint this week and is set to return in a week or two. Sending him to the 60-day disabled list is mostly a procedural move.
In 13 games in April, Hermida hit .250 (6-for-24) with two RBIs.