Last week’s news that the Mariners' would further expand protective netting around Safeco field was followed a day later by word that all Major League Baseball teams would do the same.

And it’s not surprising.

Mariners president and CEO Kevin Mather issued a statement saying the team is concerned about fan safety, which is no doubt true. No MLB team I know of wants their fans knocked unconscious or to lose teeth or fingertips because of a screaming line drive.

But it appears more likely the main driver behind MLB’s changes is the increased potential for a successful lawsuit by injured fans struck by foul balls or pieces of flying bats. At least one prominent national sports attorney agrees the changed dynamic of how fans pay attention to games has left MLB and its teams worried about being vulnerable to litigation despite the longstanding legal protections they enjoy.

“I don’t think venue owners are monsters, and I think there certainly is some empathy to wanting to keep their patrons safe,” said Timothy Liam Epstein, a sports attorney and partner at the Duggan Bertsch LLC firm in Chicago. “But at the same time, yeah, lawsuits are driving it. That’s what happens in sports.”

The NHL changed its protective netting in 2002 after a deflected puck struck Columbus Blue Jackets fan Brittanie Cecil, 13, at a game. She died two days later...