McEntire will perform on a Friday night during playoffs for the international youth baseball tournament, whose games are played at the adjacent Ripken Baseball Complex.
Aberdeen Mayor Mike Bennett said Monday the McEntire tickets are expected to go fast.
"They've already had a great deal of interest," Bennett said during a meeting of the city council.
Tammy Lowry, of Aberdeen-based TNJ Entertainment, said Tuesday that about 1,200 tickets have already been sold since sales began Saturday.
"Everyone is very excited about it. People were asking me, 'Is it the real Reba?'" Lowry said with a laugh. "We generally don't get acts of that nature [in Aberdeen], so the response was pretty overwhelming."
In addition to her country music fame, Reba McEntire is also a TV star from the show bearing her name "Reba."
Lowery said the idea of Reba coming to Aberdeen began with a conversation with Bennett, but Ripken Stadium officials proposed having the event during the World Series.
"They thought it would be a great idea to do a concert during the World Series," Lowry said, noting Ripken Baseball is also having an opening parade and a carnival for the event this year.
"[Cal Ripken Jr.] is really, really trying to make it an experience for the kids," she said. "We are definitely pretty excited about it."
Lowry, a past president of the Aberdeen Chamber of Commerce and an economic development board member in the city, said she hopes the show can boost Aberdeen's economy.
"We expect people to stay at our hotels, eat at our restaurants and make a day of it," she said.
Tickets are available through the Aberdeen IronBirds website, ironbirdsbaseball.com.
Seats range in price from $45 to $125, but according to the website, only field seats and reserve seats are still available.
McEntire has eight shows scheduled in the U.S. and Canada beginning July 21, according to her personal site.
McEntire is one of the best-selling female country artists of all time and was named the third top country artist of the past 25 years by Billboard Magazine.