KANSAS CITY -- Brady Singer's 18th pitch in the first inning in Tuesday night's 6-4 win over the Indians caused both Whit Merrifield and Salvador Perez to run to the mound and signal manager Mike Matheny and trainer Nick Kenney in the Royals’ dugout.

Minutes later, Singer was exiting the game.

The right-hander was diagnosed with right upper arm discomfort, the Royals announced later in the series opener at Kauffman Stadium. But after initial imaging on Tuesday night, Singer and manager Mike Matheny expressed that they were less concerned than when he originally walked off the mound two outs into the game.

“You could see something didn’t feel right,” Matheny said. “... We already had a picture taken and everything came back good. Not the elbow, or the or shoulder. More mid-arm. The good news is that it wasn’t shoulder or elbow.”

Singer allowed three runs before he exited, with the first four Cleveland hitters reaching on a double, walk and two consecutive singles before he induced a double-play ball.

In a 2-2 count against Bradley Zimmer, Singer threw a slider and grimaced as he finished the delivery. That’s when Merrifield ran to the mound, and as Matheny walked to the mound, Merrifield kept shaking his head. Singer talked with Matheny and Kenney briefly before heading into the Royals’ clubhouse.

“We always go out there and have aches and pains,” Singer said. “But tonight, on the last two pitches, I could feel it grab a little bit more than normal, which concerned me. But you always have those little things going, everybody does.”

Singer said this pain was something he’s dealt with before -- he missed three weeks earlier this season with right shoulder fatigue -- but he has been able to pitch through it a few times. On Tuesday, he felt pain on the last two sliders he threw and couldn’t shake the feeling.

“Not much leading up to it,” Singer said. “I threw a few sliders to Zimmer, and the last one got me, just grabbed there in the middle part of my arm. But I’m starting to feel better and not overly concerned about it.”

Singer would be on schedule to pitch the Royals' final game of the 2021 season on Sunday, when they host the Twins at Kauffman Stadium, but the club hasn’t announced its weekend rotation plans.