DETROIT -- When Miguel Cabrera led off the Detroit fourth inning with a wicked line drive that caught Kansas City pitcher Zack Greinke in his right arm, Royals manager Trey Hillman gasped.

"It was very scary. I think it was very scary to anybody who cares about Zack Greinke," Hillman said after the Royals' 9-2 victory. "I think everybody took a gasp. I wasn't real sure what I was going to see when I got out there."

What he saw was the imprint of the baseball seam above Greinke's right elbow. Despite that severe impact, the pitcher retrieved the ball and threw out Cabrera.

Catcher Miguel Olivo raced to the mound.

"I thought it hit the glove," Olivo said. "I went and asked, and he said, 'I'll be fine.' "

After being tended to by assistant athletic trainer Frank Kyte, Greinke took nine or 10 practice pitches to test his arm.

"[My] control was really bad, and I just had to make sure I could throw strikes and not just go out there and walk people," Greinke said. "I told Trey I needed a bunch."

Finally the blood started flowing through the stricken area, and he stayed in the game. His next official pitch was an offspeed strike to Aubrey Huff, who proceeded to strike out. Greinke returned to pitch a perfect fifth inning with two strikeouts. But after Josh Anderson's three-run homer made the score 8-0, Greinke was removed from the game.

Whether or not Anderson hit the homer, Hillman had decided Greinke's day was over. His American League Cy Young Award candidate was going for X-rays, which were negative, and treatment on that arm. Greinke didn't argue.

"He would've come out. He might have balked at it, but he didn't," Hillman said. "He's pretty level-headed and he has been all season about how he feels."

Left up in the air was if Greinke would make his next scheduled start on Tuesday against the Boston Red Sox at Kauffman Stadium.

"We'll see how it goes," he said. "I mean, I'm sure it'll get worse than it is today, but we'll see how it comes back. It'll probably be fine, but I don't really know."

Greinke remembered that he was drilled in 2005, also at Comerica Park by a Carlos Guillen sizzler, but was able to make his next start. This one, though, feels worse.

This painful episode came after a fine start in which he struck out five batters in the first two innings. In his five shutout innings, Greinke struck out eight to reach the 224 mark and gave up three singles and two walks. His Major League-leading ERA sank to 2.14.

After the injury, the Royals' trainers and staff were on alert.

"He was OK, but I didn't want to push it past the fifth," Hillman said. "I'm glad he got the win, but I wouldn't have hesitated to take him out if he couldn't locate or if he changed his delivery. He had six or seven sets of eyes on him to see if anybody noticed anything."

All things considered, Greinke considered himself rather fortunate.

"Really, the only thing that's bad is if it hits you in the face," he said.