The Cubs declined to comment.
Soler, 20, a 6-foot-4, 225-pound corner outfielder, was considered by many to be the next big Cuban prospect on the scene after outfielder Yoenis Cespedes, who signed with Oakland earlier this year for $36 million over four years.
Soler, who was declared a free agent last week, was being courted by several teams, including the Yankees, Blue Jays, White Sox, Marlins, Phillies, Orioles and Red Sox.
The prospect has to sign with a Major League club before July 2 or be subjected to new Basic Agreement guidelines, which will limit spending on international prospects to $2.9 million per team without penalty.
Right-handed pitcher Armando Rivero, outfielders Henry Urrutia, Gerald Sanchez and teenage left-handed pitcher Omar Luis, who are all from Cuba, were also declared free agents with Soler and remain on the market.