Smyly missed most of Spring Training with left shoulder tendinitis and the rehab that followed. Since returning to make his season debut on April 24, he's made three starts, but his last one against the Red Sox on Tuesday in Boston brought problems.
"Yeah, I started feeling it in Boston," said Smyly on Saturday. "Just kind of kept pitching through it. And the next day it didn't respond well.
"You've got so much adrenaline, it's not like it was affecting my pitching [in Boston]. But [it was] definitely getting tight and stiffening up. And it didn't feel loose, it didn't feel smooth."
Smyly allowed one earned run in six innings and took the loss in a 2-0 Red Sox win. Prior to going on the DL, he had been scheduled to start for the Rays against the Rangers on Sunday.
When asked if what he's feeling any different than what he felt during Spring Training, Smyly replied: "Hard to describe. It's a shoulder -- any time it's a shoulder, it's scary. But, obviously, I'm not good enough to pitch right now."