The left-hander, who pitched in his first All-Star Game this month, was placed on the 15-day disabled list Wednesday, retroactive to Monday, with left elbow soreness. Consequently, the Rays recalled infielder Ryan Roberts from Triple-A Durham.
"I'm not sure exactly what caused it or if there was something that caused it," said Moore, who is 14-3 with a 3.41 ERA in 21 starts. "It's kind of a fortunate situation that something like this did have to happen with the amount of off days (ahead) and as well as we're throwing the ball right now."
Moore said he experienced the elbow pain while throwing change-ups in the second inning of his latest start Sunday against the New York Yankees, which resulted in a no-decision in a Rays loss at Yankee Stadium. He did not tell manager Joe Maddon about the pain until leaving the game after five innings.
On Wednesday, Moore played catch with Rays head trainer Ron Porterfield to determine the pain's severity. He said he felt fine from 45 to 60 feet away, but the soreness became stronger with about 70 feet of distance between them.
Moore said an MRI revealed everything is fine with his elbow structurally and that the inflammation, as far as he knew, was normal.
"This is definitely the best decision for us going forward," Moore said. "I think that if this was the playoffs and a situation called for me to be out there, I think without doubt that I could do it ... There's not a reason for us to push things right now."
The Rays are optimistic that Moore's DL stint, the first of his career, will be brief. Maddon said he doesn't anticipate that rehab starts will be necessary. He said Moore could return after Tampa Bay completes a five-game road trip against the Arizona Diamondbacks and Los Angeles Dodgers from Aug. 6-11.
"I do believe that he can be over with it the moment he goes through this little rehab with Ronnie," Maddon said. "I believe it can go away ... Everything sets up to the point where let's just back off. The schedule is in our favor. Theoretically, he may miss one start and get back after the road trip and everything will be cool at that point."
Moore's injury means the Rays will use a four-man rotation of left-hander David Price, right-hander Jeremy Hellickson, right-hander
Chris Archer and right-hander Roberto Hernandez. Maddon had considered using a four-man rotation before Moore's injury, because the Rays have four off days between Thursday and the start of a six-game homestand on Aug. 13.
"Any time you're dealing with a pitcher and his arm, you have some degree of concern," said Andrew Friedman, the Rays' executive vice president of baseball operations. "But I think how he feels ... everyone feels good about it and so does Matt. We're just being really cautious right now. The off days afford us an opportunity to do that, and we're going to make 100 percent sure that he's healthy when we send him back out there."