According to USA Today's Bob Nightengale, Lee left the mound holding his elbow. The Philadelphia Inquirer's Matt Gelb reported he "threw an 85-mph cutter, yelled an expletive, and waved his arms in disgust."
Lee had just returned a week ago from a two-month stint on the disabled list with a left-elbow strain. Thursday's start was just his third since his return. He had been considered a prime candidate for a waiver-market trade in August if he could prove he was healthy, as the New York Yankees, Toronto Blue Jays, and San Francisco Giants were reportedly interested.
Lee, who will turn 36 next month, still has roughly $37.5 million in guaranteed money due to him after this season.
Lee was replaced Thursday night by Antonio Bastardo.