The person spoke late Sunday night on condition of anonymity because the deal was pending a physical sometime after Christmas and had not been announced.
Ryu was 14-5 with a 2.32 ERA for the Los Angeles Dodgers last season. He made his first All-Star team and finished second in NL Cy Young Award voting to New York Mets ace Jacob deGrom.
Ryu's deal raised agent Scott Boras' total to $1,016,500,000 in guaranteed contracts for seven players since the start of November, deals extending as many as nine seasons. He previously negotiated agreements for pitchers Gerrit Cole ($324 million), Stephen Strasburg ($245 million), Dallas Keuchel ($55.5 million) and Tony Watson ($3 million); third baseman Anthony Rendon ($245 million) and infielder Mike Moustakas ($64 million).