Galarraga, who turned 26 years old last month, made his big league debut last September with Texas after spending most of the year at Double-A Frisco in the Rangers organization. Primarily a starter, the right-hander went 9-6 with a 4.02 ERA for Frisco, averaging just under six innings a start while striking out 114 batters over 127 2/3 innings. He tossed two complete-game shutouts at Frisco and another at Triple-A Oklahoma, where he posted a 2-2 record and 4.74 ERA in four starts.
With the Rangers, Galarraga made two relief appearance before earning his first Major League start on Sep. 24, when he gave up five runs on four hits and four walks over 4 2/3 innings against the Angels. For his career, Galarraga has a 27-42 record with a 4.26 ERA and 540 strikeouts in 632 innings.
The Rangers designated him for assignment on Jan. 25 to make room for Jason Jennings on their 40-man roster. The Tigers placed him on their 40-man roster, taking the spot of recently released Tony Giarratano.
"Galarraga is a quality prospect with a quality arm," Tigers general manager Dave Dombrowski said in a statement. "His acquisition adds depth to our roster, and he is a pitcher we feel will be able to help our club in the future."
Hernandez, 24, put up 24 home runs and 106 RBIs between Class A Lakeland and Double-A Erie, establishing himself as a power-hitting outfielder. Twenty of those home runs came at Lakeland in the pitcher-friendly Florida State League. He combined for a .259 average between the two stops and has a .267 average and 37 home runs over 221 career games.
The Rangers assigned Hernandez to their Frisco roster.
Jason Beck is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.