A revised form of head protection was approved Friday by Major League Baseball for pitchers to begin using immediately if they choose.

MLB approved a padded cap for pitchers for the first time last season, but only one big leaguer wore it in action.

Pinwrest, the manufacturer, removed the padding from inside the isoBLOX cap it introduced last year in favor of detachable padding to wear over a standard cap. Patrick Houlihan, baseball's vice president and deputy general counsel for labor relations, told "Outside the Lines" that all 30 teams were informed via email Friday afternoon that the new product passed independent laboratory testing.

Padres pitcher Alex Torres was the only big leaguer to wear the protective cap last season. Kent C. Horner/Getty Images

"It's ready for prime time," said Bruce Foster, CEO of 4Licensing Corp, Pinwrest's parent company. The revision, he said, addresses pitchers' complaints that the cap with interior padding and an extended bill hindered comfort, depth perception and the ability to hold runners on.

San Diego's Alex Torres was the only major leaguer who decided to wear the first MLB-approved padded cap for pitchers in games last season. Meant to provide some protection of the head against line drives, the isoBLOX cap was more than double a standard cap's size and weight, and its bulky appearance also was a turn-off for pitchers.

New York Yankees pitcher CC Sabathia told "Outside the Lines" last month, "I definitely like the idea [of reducing the risk], if they can come up with something that wouldn't be too strenuous on your head." The 2014 isoBLOX cap, Sabathia said, was "too big" and a "little too heavy," especially for the heat of summer.

The weight of the new cap and padding combination is "approximately the same" as last year's integrated model, Foster said. "The feel of the cap is consistent with what players are used to -- this is the next step that had to happen.

"It's not something that'll be offensive to anybody because it doesn't look cool."

But will pitchers take to wearing caps with the padding on the outside after all but one rejected having it on the inside? MLB Players Association assistant general counsel Bob Lenaghan said, "I don't know, that's a very good question."

Foster said the "one size fits all" padding should be widely available to pitchers in spring training beginning next week. Made of plastic injection molded polymers combined with a foam substrate and customized to match the colors and logos of teams' official New Era caps, the padding is secured to the cap by an adjustable strap.

Houlihan said the new isoBLOX product, like last year's, earned approval of MLB and the players' association after meeting a safety standard at 83 mph -- which was determined to be the average speed of liners reaching the mound. Industry sources say protection against higher speeds requires bigger, harder and heavier headwear, such as a helmet, but even the official Rawlings MLB batting helmet is not billed as a fail-safe device against baseballs traveling faster than 100 mph.

The new isoBLOX approach increases padded coverage by about 20 percent, improving protection of critical regions -- like the temples -- against catastrophic injury, Foster said.

"Our first priority is making sure of safety," Houlihan said, "and hopefully this product that is worn over a normal cap will be more user-friendly and versatile for pitchers to try on and determine if it's for them."

According to Houlihan, MLB remains open to alternatives from the makers of isoBLOX and other sources. And Lenaghan said, "We're trying all kinds of ways, we're not abandoning the inside-the-cap idea."

"We've never seen this as an exclusive space," Houlihan said. "We continue to receive interest from competing companies and wouldn't rule out the possibility of one having something to pass our standards by the end of the season."

In August, after then-Miami Marlin Dan Jennings became the seventh pitcher in just under two years to be struck in the head by a line drive, MLB and the union told "Outside the Lines" about their joint initiative with the California-based company Boombang to develop protective headwear for pitchers. Houlihan said the project is "still going full speed ahead" and he anticipates results in about a year.

The last three years MLB officials have said they have not considered for approval protective headwear extending beneath the cap line, although several pitchers suffered serious injuries when struck beneath it.

Houlihan acknowledged that he and colleagues involved in this issue took notice when an Australian cricket batsman died in November, two days after a ball struck him on the top of the neck. Phillip Hughes, 25, was hit beneath the helmet line by a bouncer, rupturing an artery.

"We keep abreast of all the incidents that could bear on solutions," Houlihan said.