In the fifth inning of Cleveland's 9-8 loss to the Orioles, Chisenhall was hit on the right arm by a 91-mph fastball from lefty reliever Troy Patton. After undergoing X-rays, the young third baseman was diagnosed with a fractured right ulna bone.
Chisenhall is headed back to Cleveland, where he will undergo surgery to repair the broken bone. The procedure, which is scheduled for some time in the coming week, will be performed by Dr. Thomas Graham at the Cleveland Clinic. Chisenhall is expected to miss at least four to six weeks.
"We had a bad feeling when the ball got him pretty good, pretty square," Indians manager Manny Acta said. "The sound of it wasn't good. It's not good news, especially for the kid."
Chisenhall left Camden Yards without speaking to reporters.
After being struck by the pitch from Patton, Chisenhall jogged down to first base, where he was quickly met by Acta and a member of the Indians' medical staff. Upon examining Chisenhall's hand, Acta motioned for Shelley Duncan to enter the game as a pinch-runner.
Through 24 games for the Indians this season, the 23-year-old Chisenhall has hit .278 (20-for-72) with three home runs and nine RBIs. He has been heating up of late, hitting at a .342 (13-for-38) clip over his past 13 games.
In Friday's contest, Chisenhall went 1-for-2 with a single and one run scored.
"He was having better at-bats," Acta said. "He handled himself well this time around. It's always tough to see a young guy getting his feet wet, doing better and then all of a sudden, having an injury like that."
Chisenhall -- a first-round pick by the Indians in the 2008 First-Year Player Draft -- has been splitting time between third base and designated hitter since being promoted from Triple-A Columbus on May 28. Chisenhall's time at third has been limited since Jack Hannahan returned on June 15 after a stint on the 15-day disabled list.
The Indians will place Chisenhall on the 15-day disabled list on Saturday and the club will recall a replacement from the Minor Leagues. At the time he spoke to the media, Acta had not yet convened with general manager Chris Antonetti to discuss the situation.
"I haven't talked to Chris yet," Acta said. "I need to sit down with Chris and discuss that. Somebody will be here."