DETROIT -- Chicago White Sox right-hander Lucas Giolito left his season-opening start on Friday because of abdominal tightness on his left side.
Giolito struck out six while pitching four innings of one-hit ball in Detroit.
"I'm concerned because he felt something," manager Tony La Russa said.
Giolito departed with a 3-0 lead, but the Tigers rallied for a wild 5-4 win.
He made his third straight start on Opening Day for the White Sox. He was 11-9 with a 3.53 ERA last season.
"We got a lot riding on him," La Russa said.