Boston placed Seigler on the 10-day injured list Wednesday due to left knee patellar tendinopathy.
Acquired from the Brewers on Feb. 9, Seigler didn't end up making any appearances in spring training while recovering from a knee injury that first surfaced while he played in the Dominican Winter League during the offseason. The Red Sox haven't indicated where Seigler stands in his recovery, so the 26-year-old appears destined to miss more than the minimum 10 days. Seigler has two minor-league options remaining and could be sent out to Triple-A Worcester to play regularly once he's activated from the IL.