Starling, the fifth-overall pick in the 2011 First-Year Player Draft, is not playing in instructional league games in Arizona due to the injury, as first reported by the Kansas City Star.
However, the injury is minor, and Scott Sharp, Royals director of Minor League operations, said the organization is being overly cautious about it.
"It's basically an inconsequential injury," Sharp said in a phone interview. "He was just running down to first and felt a little something in his quad. As we tell all our athletes, obviously, if you're feeling anything, let us know."
The 19-year-old might not play again until Spring Training, as the instructional league's 17-game schedule concludes on Oct. 21. Starling continues to work out at the club's facilities in Surprise, Ariz., but Sharp doesn't think he'll play in any more games, to ensure he doesn't aggravate the injury.
Sharp said Starling was one of the few players in camp to play every day and easily got the most at-bats of any Royals Minor Leaguers on the team. The Gardner, Kan., native didn't get much baseball work in during the summer, as he did not sign until right before the Aug. 15 deadline. Still, Sharp said they saw "a lot of growth" from Starling in the roughly 30 at-bats he got.
Sharp was adamant that the injury is nothing serious.
"He can work out and he can do all the normal stuff, and really, if this were in-season or a championship-season environment, I don't think you and I would have this discussion, because knowing Bubba, he'd be playing," Sharp said.
Adam Holt is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.