MLB staff have said a cap liner with Kevlar, the material used in body armor for the military, law enforcement and NFL players, is among the ideas under consideration.
The liners, weighing perhaps 5 ounces or less, would go under a pitcher's cap and help protect against line drives that often travel over 100 mph.
"We are actively meeting with a number of companies that are attempting to develop a product, and have reviewed test results for several products," MLB spokesman Pat Courtney told the AP in an email after Happ was injured. "Some of the products are promising. No company has yet developed a product that has satisfied the testing criteria."
Several pitchers around the majors sounded resistant - even after seeing replays of Happ's injury.
"You know the risks," Angels lefty C.J. Wilson said. "Guys get hurt crashing into fences. Guys get hurt tripping over first base and blowing their knee out. This is professional sports, and we are paid well to take those risks."
Colorado Rockies left-hander Jorge De La Rosa said if a helmet or liner is developed for pitchers, he'd gladly wear one.
"It wouldn't be hard for me," De La Rosa said. "To protect against those kinds of things, it's good for us."
Cincinnati Reds pitcher Homer Bailey doesn't like the idea of wearing protective headgear.
"The game's been played a long time. Situations like that are unfortunate, but we have to keep it our game," he said. "I don't think you have to adjust the whole program."
And Seattle Mariners right-hander Aaron Harang thinks it would be difficult for veteran major league pitchers to adapt to new equipment.
"I know it's a hot topic," he said, "but I don't think it's a problem that's easily solved. I know a lot of people want pitchers to start wearing helmets. It's a good idea in theory, but I don't know how practical it is
