Ross stumbled as he approached first base on a groundout, then fell to the field and grabbed his right leg.
He was grimacing in pain as he was loaded on the cart and taken off the field.
"They took him to the hospital and put it back in," Diamondbacks manager Kirk Gibson said. "They are doing more tests on him to make sure there is no fracture and just evaluate the damage. It is possible he could have surgery, but they have not determined that yet."
The Diamondbacks moved Martin Prado from third base to Ross' spot in left field. Matt Davidson came in at third in his major league debut. Arizona lost the game, 9-5.
Information from The Associated Press was used in this report.