Alexander Poulides said he grabbed a banana from a catering cart at San Francisco's AT&T Park and threw it toward the field in frustration.
It landed near Orioles outfielder Adam Jones, who is black. Many people interpreted the gesture as a racist insult -- it doesn't often happen in the U.S., but it a well-known slur in Europe -- but Poulides denied that was his intent.
"I'm embarrassed and shocked by the outcome,'' Poulides said. "In hindsight, I wish I didn't do it and I apologize. I'm very sorry."
The Giants said they were unable to confirm if Poulides was indeed the culprit and would continue to investigate.
"We would like to extend our sincerest apologies to Adam and the entire Orioles organization for this unfortunate incident," the team said in a statement. "The inappropriate actions of this individual in no way reflect the values of our organization and our fans."
"The Giants have a zero tolerance policy against this type of behavior, which results in immediate ejection from the ballpark. While we have been investigating the matter since we learned of the situation, unfortunately we have been unable to identify the person responsible."
The Giants lost to the Orioles 10-2.
'SNL': 'Anchorman 2' cast, One Direction sing 'Afternoon Delight' [VIDEO]
Reindeer recovered after escaping from Santa during lighting ceremony