With runners on second and third and Mitch Moreland at the plate, Jewell uncorked a wild pitch. He raced to the plate to cover and appeared to slip before getting there, with his right ankle getting caught beneath him.
The right-hander remained down on the ground for several minutes before a stretcher was wheeled out to home plate. He was taken to a local hospital.
"He's getting evaluated, I think, at Massachusetts General,'' Angels manager Mike Scioscia said. "Hopefully we'll get an idea of what's happening sometime tonight."
The Martinez run counted, giving Boston a 9-6 lead that would hold as the final score.
Jewell had just been recalled from Triple-A Salt Lake City before the game.
The Associated Press contributed to this report.
Jewell leaves game on stretcher after leg injury
Angels reliever Jake Jewell goes to field the ball at home plate and his right leg gets caught underneath him. He'd leave the game on a stretcher.