Ryu made headlines on April 23, 2003, when he knocked an osprey from its perch by throwing a baseball at it at Jackie Robinson Ballpark in Daytona Beach before a game in the Single-A Florida State League causing it to die 6 days later.

[1] Ryu made his major league debut with the Chicago Cubs on May 14, 2006, in a relief appearance against the San Diego Padres.

He would return to the Cubs for late August and September making several bullpen appearances, faring slightly better and finishing the year with an 8.40 ERA.

[2] Ryu was traded to the Tampa Bay Devil Rays on February 14, 2007, in exchange for minor leaguers.

However, Major League Baseball declined the waiver claim on April 1, and Ryu was returned to the Padres, then released.