Ventura said afterward through interpreter Christian Colon that the trainers told him he likely would get an MRI either Saturday or Sunday, but that no one was certain what caused the condition.
Ventura said he felt numbness in his right thumb and two outside fingers.
"It just didn't feel right," Ventura said. "It felt numb."
Ventura added that he never has experienced this injury before. He also feels that he is letting the team down.
"I feel when this happens, I feel bad because I want to be there and help the team win," he said. "But I've been going through these things. ... I don't know. I will just try to get with the trainers and get this worked out."
Royals manager Ned Yost said he and pitching coach Dave Eiland thought something was wrong in the third inning.
"Dave and I were looking at it early on because his velocity was down," Yost said.
Yost's level of concern?
"We'll just see tomorrow," he said. "Of course you have a level of concern, but you wait until tomorrow to evaluate again.
"I'm not speculating anything about it. ...[trainer] Nick [Kenney] was afraid Yordano might have to alter his mechanics because of the numbness and his recommendation was to get him out of there. Now we wait until tomorrow."
Jeffrey Flanagan is a reporter for MLB.com. Follow him on Twitter at @FlannyMLB. This story was not subject to the approval of Major League Baseball or its clubs.