Semien was diagnosed Monday with a Grade 3 left hip flexor strain and is expected to be out for 4-to-6 weeks, at a minimum, Jon Heyman of the New York Post reports.
Semien initially tried to play through the injury, but it was too debilitating and he eventually landed on the 10-day injured list Thursday. While the 35-year-old infielder is shelved, the Mets will continue to use Brett Baty as their primary second baseman, with Ronny Mauricio also in the mix for some starts.