The Indians outfielder was transferred to the 60-day disabled list on Sunday with a broken hamate bone in his right hand. Brantley will have surgery early this week and will need six to nine weeks to recover.
"It's believed that that's the source of his most recent symptom presentation," said Lonnie Soloff, the Indians' head athletic trainer. "The treatment of that is excision of the hamate, removing that part of the hamate bone."
Soloff said Travis Hafner, Jim Thome and Carlos Santana have all undergone a similar operation in the past.
Brantley first felt soreness in his right wrist on the team's trip to Boston at the start of the month. He sat out the final two contests of that four-game series. Soloff said the pain originated in the ECU tendon in his wrist.
"About 10 days later, he came to us with complaints of pain in the palm aspect of his hand," Soloff said, "which at that point, has to increase your suspicion for a hamate injury."
Brantley tried to play through it, avoiding a trip to the 15-day DL until he was placed there on Friday. He had sat out three of Cleveland's four games against Seattle at the start of the week.
The pain prevented him from being able to properly grip a bat. Soloff said it remains unclear if the injury to the hamate bone triggered the pain in Brantley's wrist.
"What is clear is his present symptoms, his inability to squeeze a bat or swing a bat, are clearly coming from his hamate," Soloff said. "The treatment there is to remove that."
The original plan was to shut Brantley down for three to five days before deciding on a recovery process while he was on the 15-day DL. That idea was scrapped when the club determined his injury was more severe.
Thomas Graham, a hand specialist, will perform the procedure on Brantley this week.
In 114 games this season, Brantley batted .266 with seven homers and 46 RBIs.
The Indians purchased the contract of outfielder Jerad Head from Triple-A Columbus and optioned left-hander Nick Hagadone. Head was batting .284 with 28 doubles, 24 home runs, 67 runs scored and 70 RBIs in 114 games for the Clippers. He made his Major League debut in Sunday's 2-1 loss to the Royals, going 1-for-3 while starting in left field.
Hagadone had been recalled on Friday, but did not appear in a game.
Zack Meisel is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.