As for adding Pimentel to the active roster, the Rangers are expected to announce another corresponding roster move once the 25-year-old joins the team.
Pimentel, who racked up a 4.50 ERA in 25 appearances with the Pirates over the past two seasons, was designated for assignment last Sunday, when Pittsburgh set its Opening Day roster. He was limited to just 20 outings for the Pirates last season due to right shoulder inflammation and a right ankle sprain.
Paul Casella is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.