The 29-year-old right-hander, who was recalled from Double-A Montgomery on Tuesday, experienced the seizure when he was walking into the visiting clubhouse to dress prior to the game.
"He's had it before," Rays manager Joe Maddon said. "It just normally takes hours to get him back and he should be back by tomorrow. ... We've gone through it before. He's fine, he's fine."
Salas is 0-0 with a 10.38 ERA in four games with the Rays this season; his last outing was Wednesday, when he walked one batter in one-third of an inning against the Yankees.
Salas began the season on the restricted list and was reinstated May 17 and optioned to Triple-A Durham. After that he was one of the Bulls' top relievers, posting a 2.62 ERA over 28 relief appearances.
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.