"I'll take it," Hairston said of his wearing No. 21, the same number worn by Sammy Sosa. "Who wouldn't want it?"
Hairston was a fan of Sosa's while attending Naperville North in the late 90's. His dad, Jerry Hairston Sr. played for the White Sox at the time while his brother Jerry played for the Cubs in 2005 and 2006.
"I used to love coming to Wrigley Field and the history, especially in the late '90s when Sammy was doing his thing," he said. "I sat in the bleachers a few times when he was hitting all his home runs. That was a good time to be in Chicago."
Hairston was reminded that Sosa recently said he thinks his number should be retired.
"(I'll) enjoy it while I can," Hairston said with a laugh. "I think it will be."
Hairston is coming off a career season in which he hit 20 home runs for the New York Mets. He signed a two-year, $5 million contract with the Cubs and is expected to platoon in right field with fellow newcomer Nate Schierholtz.
He learned he was being given No. 21 via Twitter.
"My wife came to me and said 'I guess you're going to be 21 this year' and I was like 'What?' So I looked online and that's what number I had. I'll take it."