Riefenhauser is 1-0 with a 7.94 ERA in five appearances for the Rays this season.
Riefenhauser "did a really nice job for us," Rays manager Kevin Cash said. "He pitched in three straight ballgames. It was nice to see him -- probably didn't have his best showing, wasn't healthy in Spring Training. Nice to see him kind of fully recover and bounce back."
Belisario, 32, went 4-8 with a 5.56 ERA for the White Sox in 2014. The veteran right-hander suffered a fractured left shoulder prior to Spring Training. He was 0-2 with a 3.26 ERA and 17 saves in 27 appearances for the Bulls.
"We'll probably fit him right back into the bullpen," Cash said. "He's a guy who throws a lot of ground balls. His arm bounces back really well. I don't think he'll have a set role. Nobody has a set role down there."