The Astros suspect that swinging a bat, not throwing a pitch, caused the right elbow discomfort that forced starter Lance McCullers Jr. to the 10-day disabled list.

McCullers grounded out in an at-bat during his last start against the Dodgers in Los Angeles. The discomfort, he said, began after that and forced him out of the game.

“There’s some conversation with our doctors about when exactly Lance felt something in his arm, and it was after the at-bat in L.A,” Astros manager A.J. Hinch said.

On Thursday, McCullers said he felt relieved to learn that he did not suffer any injury to the ligaments in his elbow.

“We’ve come to the conclusion that it’s a swinging injury, from batting,” he said.

Hinch has campaigned to implement the designated hitter in both leagues to increase offense and avoid injuries like the one to McCullers, a 24-year-old with 10 at-bats.

“Anybody want to vote for the DH now?” Hinch said before Thursday’s game against the Mariners. “That will only strengthen my conviction for universal rules,” Hinch said.

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