BOSTON -- After Nathan Karns threw his bullpen on Tuesday, the Rays decided to shut down the right-hander for the remainder of the season rather than have him make one additional start.
"He came out in the bullpen role in Detroit and tweaked his arm a little bit," Rays manager Kevin Cash said. "We're very confident it's nothing major, but he's rehabbed, rested, gotten treatment, came out and threw a really good simulated BP today. But I think after the fact, we made the best judgment for him going forward. It doesn't make much sense just to try and squeeze six innings in. Let's just shut him down on a good note."
Cash said Karns has forearm tightness, but he sounded confident the injury isn't more severe.
"Sim game, [he] felt good," Cash said. "It's not completely out of there. I think he'd be the first to tell you if this was something that was going on. Midseason he's pitching. Probably doesn't even miss anything.
"We've asked quite a bit out of Nate Karns this year, and he's been tremendous for us. The last thing we want to do is risk anything negative here with 10 or 12 games to play.
Karns finished the season at 7-5 with a 3.67 ERA in 27 appearances (26 starts), logging 147 innings.
"He's been outstanding," Cash said. "When we were going really good as a team, he was right in the thick of that. I think he's evolved as a starting pitcher. There's no doubts there's been times when people have questioned his limits for going back out for the sixth or the seventh, different scenarios. He's handled it incredibly well for a young pitcher.
"I think the greatest thing is Nate Karns learned quickly about how to pitch with runners in scoring position. And kind of calmed those moments and did a really good job of learning that on the fly and making the most of those opportunities.
"He bowed up. He's been outstanding."
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.