Hu was recalled from Triple-A Durham on Thursday, Roger Mooney of the Tampa Bay Times reports.
The Rays were in need of bullpen health after Erasmo Ramirez (personal) was placed on the paternity list, so they decided to bring Hu back up for his second cup of coffee in the big leagues. The 23-year-old fired one scoreless inning in his late-April debut, although he'll likely head back to the minors once Ramirez rejoins the team in a few days.