Jon Lester had no excuses for his performance after Boston's 18-3 loss to Texas on Tuesday night.
"It was one of those nights I flat-out stunk," Lester said.
Lester lasted only two-plus innings. He was charged with seven earned runs on eight hits and four walks.
"They have good hitters," said the left-hander, whose ERA ballooned to 5.82.
"They fouled off some good pitches, hit some bad pitches, hit some good pitches. When I made adjustments down with the ball they hit some on the ground up the middle, found some holes. That being said, when I didn't make pitches, they hit the ball hard."
Lester: 'I Flat-Out Stunk' Against Rangers