OAKLAND -- The Rangers have placed right-hander Yu Darvish on the disabled list with discomfort and tightness in his throwing shoulder. Left-handed reliever Alex Claudio was called up to replace Darvish on the roster.
Darvish had made just three starts in his return from Tommy John surgery before beginning to feel the discomfort. He left his most recent start, on Wednesday, after five innings and continued to experience tightness over the weekend in Seattle.
He flew to Dallas and underwent two MRI exams, one on his neck and the other on his shoulder.
"There were no acute findings in either MRI, which is a good thing," general manager Jon Daniels said. "Nothing structural that was a cause for concern. Yu still has a level of discomfort, so we are going to put him on the DL and give him time to recover."
Darvish underwent the elbow reconstruction surgery on March 17, 2015.
"We categorize this as not unusual coming back from surgery, to have a little issue in another area," Daniels said. "We are going to treat it cautiously, get it out of there and get him back out there."
Darvish will not throw until the discomfort is gone.
"We'll play it by ear based on how he is feeling," Daniels said. "He wants to be out there and has worked hard to get out there. We'll just have to ride this out."
Cesar Ramos started for the Rangers on Monday night in place of Darvish. The Rangers also have veteran right-hander Kyle Lohse at Triple-A Round Rock as well as Nick Martinez amd Chi Chi Gonzalez, and Daniels said there is a good chance Ramos will stay in the rotation.
"We are going to talk about that," he said. "That would be my initial thought. We'll talk about that and see what the upcoming matchups are. We definitely have a comfort and confidence in Cesar."
A.J. Griffin, who is on the DL with inflammation in his right shoulder, is scheduled to make his second rehab start for Double-A Frisco on Tuesday. The goal is 55 to 60 pitches; he would likely need one or two more starts after that before he is an option at the Major League level.
T.R. Sullivan has covered the Rangers since 1989, and for MLB.com since 2006. 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.