Arm injuries are at an all-time high in baseball, and teams are doing more work than ever to figure out why - and to figure out how to get an edge, medically, on other organizations. More than 50% of pitchers end up on the DL each year, on average for 2+ months, and 25% of MLB pitchers have undergone Tommy John surgery.

On this episode of Hardball Society, Phil Mackey and Justin Musil dive into the arm injury epidemic - with help from Yahoo! MLB columnist Jeff Passan (22:00), who authored the book, "The Arm: Inside the Billion-Dollar Mystery of the Most Valuable Commodity in Sports," and Dan Christoffer, a former Los Angeles Dodgers organization trainer who currently works in the Mayo Clinic sports medicine department.

Topics covered on this episode:

- Is it possible for scouts to spot arm injuries before they actually happen?

- In Jeff's time spent researching and writing this book, what made him stop and think the most?

- Stories about how pitchers dealt with sore elbows before Tommy John surgery was prevalent

- How much do pitch counts matter? How much does velocity matter?

- What do teams know, and what are they still trying to quantify when it comes to arm injuries?

- What will pitching staffs look like in the future? (From pitch counts... to rotations... etc.)

- MUCH more!