Texeira was added to the Royals' disabled list on Sunday.
"My arm was hurting for a while but that's part of the game - you never feel 100 percent," he said. "But my arm got to hurting so bad I couldn't keep the ball down."
After being claimed on waivers from Seattle on June 3, Texeira pitched in 27 games for the Royals with a 6.00 ERA. But he was hit hard in his last five appearances, giving up 15 hits and 10 runs in nine innings for a 10.00 ERA.
He was used primarily as a middle-inning reliever.