If only it was just about trying to make a fashion statement.
The 30-year-old Jaso is of the majority who prefer the titanium type for its lightness. Teammate Stephen Vogt did, too, but both are willing to carry a little extra weight if it means the slightest difference in preventing another concussion.
There is no study that shows it will, but so long as Jaso believes it, that's what matters.
"Being able to make some kind of adjustment gives me hope I can somehow stop it from happening again," he said. "Now, that's probably not true, because we're putting our faces right in the danger zone, but it's about not being complacent. If I did make an adjustment to better protect myself, then it would ease my thoughts a bit."
Red Sox catcher David Ross has been there. He, too, ditched a hockey-style mask in favor of a steel mask after sustaining two concussions that led to more than two months of recovery time last year.
Speaking by phone from the Red Sox's training facility in Florida this week, Ross empathized with Jaso.
"You don't want to go back into that bad situation you were in, so any way you can help take that nervousness away helps," Ross said. "I don't think studies have shown that one's safer than the other, so that's really the main thing, is peace of mind.
"When the mask is off, you feel like some of that impact is going away from your head. That's the way I like to think of it."
"Boy, it would be nice if we did have those kind of studies," said Dr. Micky Collins, the University of Pittsburgh Medical Center concussion specialist who treated both Jaso and Ross. "I think that a research project like that could be easily done to study that exact question, but the reality is at this moment we don't have that data, and I like to be evidence-based when making recommendations. Right now, it's really about personal feel. I think John felt going this way was the right thing to do, and I support that."
Titanium masks, designed by Nike with help from Jorge Posada, were made to pop off on impact to lessen some of the force of a blow to the head. But they often don't give, and the catcher ends up absorbing all of it. Steel masks have better give and are constructed with thicker padding.
Ross noted better vision thanks to the closer fit of his hockey mask, but that design was also the reason he stopped wearing it.
"The hockey mask," Ross said, "it's a louder hit, because the bars are so close to your face. But this steel one seems to take some of that blunt force away from it, in part because those bars are further away."
Jaso remembers seeing one of Ross' old hockey masks in Collins' office last year, joking that "he must've retired it there." Asked about this, Ross laughed and said, "I guess you could say that."
It was Collins who definitively told Ross he would return to the field, even though for weeks the veteran catcher had a difficult time believing it. He went 68 days between games but has since been symptom-free.
"Honestly, I thought my career was over," he said. "I kept thinking about Mike Matheny and his concussion and what happened. Micky is the absolute best. He saved my career, and I ended up being a World Series champion.
"The hardest part is having the patience when you can't see your injuries. It's not like we had surgery or had a cast on. It's your brain, and there's not even an image where they show you, 'Here, this is where you're messed up.' It's tough to come to grips that you're hurt, and yet you have all these crazy symptoms that you can't really put your finger on and tell people about. It's hard to explain and not sound like a wimp, and we don't do well just sitting and waiting to get better."
Jaso, too, went stir-crazy. An avid reader, he was not allowed to even pick up a book. Back at the field, he felt helpless, as his teammates pushed on to the playoffs. Each morning when he woke, he heard buzzing.
"Everything feels back to normal," he said. "I'm ready to get going again since I haven't played in so long. The swing's a little slow to get going, which is normal, but I'm seeing the ball well catching bullpens."
Jaso wants to stay behind the plate in a platoon role he served so well last year, hitting .282 with a .405 on-base percentage in 181 at-bats against right-handers. But the A's are also relying on him to pick up a good number of the DH at-bats they lost when trading Seth Smith to the Padres.
This would also allow them to potentially keep two of their other three catchers on the Opening Day roster.
"I know he's excited to get back there," manager Bob Melvin said. "He wants to catch; he wants to be part of the pitching staff and not just a one-way player."
The most important thing, Collins says, is he does not have to be.
"There's a reason why we hold patients out of play," he said. "They're not ready to absorb that blow again. The worst thing you can do is not recover before you suffer another one. We've made tremendous progress in how we assess this injury and treat it, and we're about doing it right and making sure all the cows are in the barn before putting these guys back in play. I feel comfortable that's been done.
"Catching is a high-risk position, and these injuries do occur. You can get hit a lot of ways as a catcher, and so if it does occur again, that's OK. We'll just have to treat them again. But it's the one injury where it's a real game-changer if it's not managed. Our outcomes are good. We don't see them again."