"He's thrown late innings out of the bullpen at Oklahoma City and he can be used in that situation, and he can be brought into the game in a short situation, as well," manager Bo Porter said.
Humber didn't have much to say about his return to the Major Leagues because he has been battling laryngitis for the last month. He whispered to reporters Tuesday that he was feeling fine, but was just having trouble speaking.
"It's not very fun," Humber said. "I'm not sick or anything, but I lost my voice and it hasn't come back."
Humber is taking the roster spot of left-hander Wesley Wright, who was claimed off of waivers by the Rays on Monday.
Brian McTaggart is a reporter for MLB.com and writes an MLBlog, Tag's Lines. Follow @brianmctaggart on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.