"He woke up a few days ago and the knee was a little puffy," Rangers general manager Jon Daniels said. "He can't think of a moment where he tweaked it. It's obviously a blow, a disappointment for him. But we'll do what we have to do to get him back."
The knee is the latest in a series of setbacks for Scheppers. He was 6-2 with a 1.88 ERA in 76 games as a setup reliever in 2013. But he pitched in just eight games in 2014 while dealing with right elbow inflammation, and dealt with the knee and a sprained right ankle last year, as he compiled a 4-1 record with a 5.63 ERA.
He went into the offseason eligible for arbitration and the Rangers showed their confidence in him by tendering a contract, despite his multiple issues. They were also openly pleased with his progress in offseason workouts at Globe Life Park.
"All winter long I saw him at the ballpark, and he had energy and a great look on his face," manager Jeff Banister said. "To not get rewarded for that is extremely disappointing and disheartening to him. But there is a competitor inside Tanner that will find a way to push through this. He'll come back and find a way to be competitive."
T.R. Sullivan is a reporter for MLB.com. Read his blog, Postcards from Elysian Fields, follow him on Twitter @Sullivan_Ranger and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.