The team has not confirmed the report.
Serrano, who defected from Cuba in April 2009, still needs to undergo a physical before he can join the Cubs. There also is additional paperwork that must be completed before the deal is finalized, a baseball source said Wednesday.
There was a report that Serrano threw a two-inning simulated game for the Cubs, striking out four and giving up one run on an infield hit, but a baseball source denied that took place.
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.