This move gets the club back to the more conventional alignment.
Hernandez was recalled by the Red Sox on April 15, only to be sent back five days later. His return gives manager John Farrell another left-handed bat.
Hernandez got three plate appearances in his initial Major League stint and had one hit and one stolen base.
Light made his Major League debut on Tuesday night in Atlanta, recording the final three outs in an 11-4 victory.
Ian Browne has covered the Red Sox for MLB.com since 2002. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. This story was not subject to the approval of Major League Baseball or its clubs.