"Billy McKinney will be out for the rest of the season," Smokies manager Buddy Bailey told Justin Rocke, the team's senior broadcast and media assistant, on Tuesday evening. "X-ray showed a hairline fracture.
"He [McKinney] is going to Chicago to see orthopedic guys and from what they see they'll determine how long he will be out," Bailey said via Rocke's Twitter account.
The 20-year-old was shelved after he fouled a ball off his right knee in the fourth inning against Charlotte on Aug. 13. He finished the at-bat -- recording a sacrifice fly -- and then left the game. He hit .285/.346/.420 with 26 doubles, three homers and 39 RBIs for Tennessee this season and .300/.371/.454 with 31 two-baggers, seven dingers and 64 RBIs in 106 games across two levels.
Drafted by Oakland in the first round in 2013, McKinney was traded to the Chicago organization as part of the Jeff Samardzija deal last July.
Alex M. Smith is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.