Jon Lester has been playing with a bone chip in his pitching elbow, and the Chicago Cubs knew about it when they signed him to a $155 million contract.
The bone chip was first discovered during a 2014 MRI before the left-hander signed his six-year deal with the Cubs, according to Yahoo! Sports, which is including the information in an upcoming book.
Lester calls the chip a "non-issue," according to the Chicago Sun-Times.