Well, this is quite a revelation. It is simultaneously extremely serious, and, by all accounts, somehow not terribly concerning.

Jeff Passan wrote an exhaustive book about pitchers, aptly titled, “The Arm,” and it’ll be released Opening Day (you can pre-order it here on Amazon), and among the many tidbits in it, there’s a section on the Cubs’ pursuit of last offseason’s big-time free agent, Jon Lester.

Sahadev Sharma got an early look at the book, and wrote about it here at The Athletic. The section that will immediately jump out at you: Lester has a bone chip in his elbow, discovered by a 2014 MRI, and described as “a little grenade float[ing] near his ligament, and at some point it would warrant surgery.”

Before freaking out, there are several important things to know:

1.) The chip, which trainers apparently suspected he has had for a long time, at most bothers Lester early in Spring Training, and then the discomfort goes away as he ramps up;

2.) The Cubs knew about the chip when they signed him to a $155 million contract last offseason; and

3.) No one has seen fit for Lester to have the surgery, which is much less serious than, for example, Tommy John surgery, but would still keep him out two to three months.

Theo Epstein discusses the chip in Passan’s book, expressing relatively little concern (again, the Cubs went big on Lester even after they knew about the chip), and adds quite a bit more in this article by Gordon Wittenmyer.

Lester is also interviewed in Wittenmyer’s piece, and he, too, seems unconcerned for now. The chip doesn’t really bother him, but he monitors the situation – if he ever feels inflamed or has to miss starts, then they’ll re-address. Until then, there’s no sense in getting in there and cutting around

So, in the end, I know this probably sounds scary, but this is not an uncommon issue for pitchers, and it’s also not necessarily something that will completely blow up Lester’s elbow and cost him a season or two. I’d encourage you to read Sharma’s and Wittenmyer’s articles, and check out Passan’s book when it comes out.

For now, we’ll just keep the revelation as something on our radar.