Olivo was penalized four games for taking part in a fight against the Mets as a member of the Marlins last season. His penalty will end after Friday night's game at Minnesota, and the Royals are expected to add a 12th pitcher from Triple-A Omaha.
"Most probably, it will be the addition of a pitcher," manager Trey Hillman said.
Catcher Matt Tupman presumably will be optioned to Omaha to make room for Olivo. During Olivo's suspension for fighting, the Royals' roster was limited to 24 instead of the normal 25.
Meantime, the Royals announced that pitcher Jorge De La Rosa has cleared waivers and had accepted an assignment to Omaha.
De La Rosa was unable to win one of the five rotation spots and was designated for assignment on March 26.
The Royals are expected to bring back a reliever from Omaha, probably Joel Peralta or Brandon Duckworth.
Reliever Yasuhiko Yabuta, testing a bruised right leg, had a good bullpen session during Tuesday's off-day, Hillman reported. He was available to pitch.
"Actually the ball got out of his hand as good as I've seen in the time he's been in a Royals uniform," Hillman said.
Second baseman Mark Grudzielanek, despite a swollen left hand, was in the starting lineup on Wednesday. He was drilled by a pitch in Monday's game against Detroit.
"I've been icing it continuously the last day and a half," he said. "It feels fine now."
In Arizona, Hideo Nomo was expected to throw a practice session on Thursday or Friday at the Surprise complex, where he was sent to recover from a groin injury. He was a candidate for a relief role until his injury.
Luke Hudson, a starter recovering from shoulder surgery in Arizona, also was expected to begin throwing after a lengthy layoff.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.