Kelley needed six stitches to close the wound caused when he was accidently kicked by fellow reliever Mark Lowe, who was visibly upset when he realized the damage one of his spikes caused.
"It kind of shocked me a little bit," Kelley said. "It happened real quick. I was going to stay out there, but when we realized there was a lot of blood one of the coaches suggested I go inside and get it checked out.
"It was a little more serious than I thought."
Kelley had the cut repaired, returned to the Peoria Sports Complex and got his throwing program in.
"The doctor told me that if I was a hockey player he would have told me to go back out there and start a fight."
But it was not a laughing matter to manager Don Wakamatsu or pitching coach Rick Adair.
"I look at those things as a positive," Wakamatsu said after the workout. "Number one, no one got hurt very bad and number two, it gives you an opportunity to address the club about what we are trying to do and what we are trying not to do. We'll treat it that way."
The incident will be discussed more forcefully during Thursday morning's pre-practice meeting inside the clubhouse.
"We talk about having fun but when we start the drills, we are extremely focused," Wakamatsu said. "I didn't see it and don't even know exactly how it happened. I assumed they were messing around and he got hurt.
"If it had happened during one of our drills, I would be even more upset. Guys get hurt by messing around and that's the message. We will enjoy our time here, but not at the expense of somebody's career. That will not happen."
Jim Street is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.