Sale, 29, posted a 2.11 ERA and a 12-4 record in 27 starts in 2018 for the Red Sox. The seven-time All-Star posted a 5.40 ERA in five innings during the Red Sox's postseason run, which ended in a World Series victory.
The left-handed pitcher owns a career 2.89 ERA and a 103-62 record. Sale's 10.9 strikeouts per nine innings are the most in Major League Baseball history. His 5.309 strikeout-to-walk ratio is also the best in baseball history.
Sale is set to make $15 million in 2019. The No. 13 overall pick in the 2010 MLB June Amateur Draft played his first seven seasons with the Chicago White Sox, before being traded to Boston in December 2016.
Sale led baseball with 214.1 innings pitched and 308 strikeouts in 2017, and finishing second in Cy Young Award voting.
He is set to start for the Red Sox on opening day when they face the Seattle Mariners at 7:08 p.m. Thursday at Safeco Field in Seattle.