Bale returned to Kansas City Sunday morning. He will be examined by team doctors, possibly as early as Monday.
Ironically, Bale was making progress with his shoulder problem and it was hoped he would come off the DL in the next few days. He threw a simulated game Friday and was due to throw live batting practice early in the week. Following Friday's throwing session, manager Trey Hillman was optimistic Bale was close to being activated.
But according to MLB.com, Hillman said the condition of Bale's arm worsened after the session, leading to frustration.
"Very unfortunate," Hillman said, according to the Web site. "He's embarrassed about it."
The 33-year-old Bale began the season in the rotation. He was 0-3 with a 7.63 earned run average, allowing 13 earned runs and 25 hits in 15 1/3 innings. The Royals planned to move Bale to the bullpen when he returned.
The Royals signed Bale following the 2006 season. He spent the 2004-2006 seasons pitching in Japan. Bale has also pitched for Toronto, Baltimore and Cincinnati. He is 3-6 with a 4.84 ERA in 56 career appearances.
For his part, Hillman was disappointed.
"I'm not pleased," said Hillman, according to MLB.com. "Players [must] think before they do things. They've got to think about how it's going to affect the rest of their team -- how it's going to affect their individual possibilities of being able to perform.
"It's very unfortunate. I hope there's something salvageable for him. But we'll just have to wait and see where it goes."
Information from The Associated Press was used in this report.