After a few minutes of consultation on the mound, Liriano departed. The Pirates said afterward that Liriano had been dealing with dizziness and flu-like symptoms, and that he would receive treatment and be re-evaluated.
"We were watching from the start [when Liriano returned to the mound for the third], and felt like we got him out at the appropriate time," Hurdle said after the Pirates' 6-1 win. "Once he started making pitches [in the third], I think it just snowballed on him."
Liriano had a nosebleed after the second inning, though he said he frequently gets them.
"I went to the hospital because of that once, but they don't know what it is," Liriano said, shrugging. "My mother and father also got nosebleeds. Today, I just felt weak."
The sudden, stunning departure of the Pirates' Opening Day starter came a couple hours after the Bucs had lost their All-Star closer and starting catcher, as Jason Grilli and Russell Martin were placed on the disabled list prior to Saturday's game.
Liriano had opened the third inning in a scoreless game by walking his mound opponent, Tyler Lyons. Liriano appeared in discomfort on the fourth-ball delivery, but turned his attention to Carpenter.
He delivered two balls to Carpenter, and the second drew catcher Tony Sanchez to the mound for a visit.
Liriano's next pitch was also outside, and it was also his last.
His head hung in both sadness and pain as Potenziano talked to him and Hurdle listened in, Liriano within minutes was accompanying the trainer to the dugout as Hurdle stayed on the hill and waved for right-hander Stolmy Pimentel to come in from the bullpen.
Pimentel earned the win after allowing one earned run in 2 2/3 innings.
Tom Singer is a reporter for MLB.com and writes an MLBlog Change for a Nickel. He can also be found on Twitter @Tom_Singer. This story was not subject to the approval of Major League Baseball or its clubs.