"I felt it in warmpups [before the fourth inning]," Pomeranz said. "My forearm was a little tight and it just stayed tight the whole inning."
Pomeranz didn't think he'd miss any time as a result of the stiffness, and manager Jim Tracy seemed to agree that a trip to the disabled list was not likely.
"I don't think that's the case," Tracy said about whether Pomeranz would need to go on the DL. "I haven't spoken further with [head athletic trainer Keith Dugger]. I don't anticipate anything serious, but he felt something in his forearm with one of the curveballs that he threw, so we went someplace else.
"It's nowhere near the elbow or anything like that. But in relation to what was coming out of his mouth, it made no sense to take any chances whatsoever and continue to move forward."
Pomeranz was making his third start of the season, and left with the game tied at 2. The left-hander allowed one earned run on five hits and three walks with four strikeouts. Pomeranz threw 67 pitches, 40 for strikes. He also singled on a hit to center in the second inning.
"I don't know if it has to do with swinging the bat or what, because I probably never swung this much," Pomeranz said. "It was just something I felt I should tell them about it, see what they had to say."
Pomeranz, 23, is in his first full season with Rockies, and is 0-1 with a 5.40 ERA. He started the season in the rotation, though he was not on the Opening Day roster, since the Rockies didn't need a fifth starter until April 15, when Pomeranz made his 2012 debut against the D-backs.
Pomeranz went 2-1 with a 5.40 ERA in four September starts for the Rockies after coming to the club as part of the Ubaldo Jimenez trade last July with the Indians.
Owen Perkins is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.