"[Wood] said it would be an honor," Epstein said.
Lester, who wore No. 31 with the Red Sox and Athletics, said the link to Wood helped convince him it was a good switch. But there was more to the decision.
"Obviously, the Chicago tie of Kerry Wood -- I remember watching him as a young pitcher," Lester said of Wood, who spent 12 seasons with the Cubs. "Obviously, the Walter Payton aspect, and for me, the personal aspect of watching Nolan Ryan -- or not necessarily watching [Ryan] but studying his career and being a part of that.
"It's always been one of my favorite numbers other than 31," Lester said. "I just felt like it was a good fit. It kind of keeps the same look to it."
Payton played 13 seasons for the Chicago Bears.
The Cubs retired No. 31 in 2009 in honor of Hall of Famers Greg Maddux and Fergie Jenkins.
"Thirty-one was a pipe dream and clearly off the table," Epstein said. "If multiple people want to volunteer it, I'm sure he would take it."
Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.