Rangers pitcher Yu Darvish left Thursday's game against the Royals due to right triceps tightness, according to MLB.com.
The injury is not believed to be serious and Darvish will be re-evaluated on Friday.
Darvis said he felt tightness in his arm before the game, according to the Fort Worth Star-Telegram. He added it's nothing to worry about, though.
"I felt some tightness with my triceps and I focused only on my location and command with my pitches," Darvish said, via FOX Sports Southwest. "Today in the bullpen I felt the tightness was more so I didn't have a lot of effort on the mound in the game. It wasn't serious so I went to the mound as usual."
Darvish was still able to pitch a scoreless first inning with just 12 pitches.