Although the plan was for Soria not to pick up a baseball for two or three days, he was throwing again on Sunday morning.
"He played catch today in the bullpen, flat ground, 30 to 35 throws just to get the blood flowing a little bit," manager Trey Hillman reported. "Didn't put anything on it. We'll see how he is tomorrow. He might play catch again, he might not."
Soria was declared out for at least three to five days on Friday because of stiffness in the back of his throwing shoulder, a situation that first surfaced on April 18 at Texas and recurred at Cleveland.
After an examination and stretching on Sunday, Soria picked up a ball.
"I believe it was actually his suggestion that he wanted to play a little catch," Hillman said. "Hopefully that's a good sign."
Hillman said the Royals are being cautious with Soria.
"He's a very valuable commodity to have in the ninth inning and I'm not going to push it, I'm not going to rush," Hillman said.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.