Bill Kostroun/Associated Press
Boston announced Sale suffered a left hip contusion and would be evaluated further, per Brian McTaggart of MLB.com.
In 2017, Sale was everything the Red Sox hoped he would be when they acquired him from the Chicago White Sox in a December 2016 trade.
The 28-year-old has landed among the top six in American League Cy Young Award voting in each of the last six seasons, including a second-place finish last year. He led the majors with 214.1 innings and 308 strikeouts last season, while his 2.90 ERA ranked sixth.
If Sale misses time at the start of the season, his absence will leave a void in the Red Sox rotation as the team fights with the New York Yankees for supremacy in the American League East.
David Price, Rick Porcello and Drew Pomeranz give Boston a strong stable of starters, but Sale is one of the few aces capable of carrying a rotation. His presence is essential if the Red Sox are going to win their third straight division title in 2018.