Over the past few months, Taijuan Walker -- like so many people around the globe -- has become curious about cryptocurrency and other 21st-century investment vehicles. That interest expanded into the wildly popular world of nonfungible tokens, or NFTs, when his friend and former Mariners teammate Jarrett Burgess alerted him to their potential.

Walker mentioned something to his agents, who jumped on the idea. And so last week, Walker became the first known Major League player to create and sell an NFT. Walker’s token, which resembles a digital baseball card, features him throwing a bullpen session in a sparkling blue uniform. His signature is inscribed over the top of it.

At their core, NFTs are multimedia properties such as images or videos, which are verified and stored on a blockchain. Walker’s card sold at auction via cryptocurrency worth more than $4,000.

“Just something to do for charity, I thought it was pretty cool to get it out there," Walker said.

Walker is tentatively slotted to pitch third behind Jacob deGrom and Marcus Stroman in the season-opening rotation. He had been scheduled to start Monday's game -- a 3-0 loss to the Cardinals in Jupiter, Fla. -- but he opted to throw on the back fields, which gave him a chance to work on his breaking pitches without worrying about results.

“The main focus was getting that curveball going,” Walker said.

Back-fields bonanza

Like Walker, deGrom will make his next start away from the lights and the cameras. deGrom’s final spring outing is scheduled for Friday, but the Mets are holding him out of their Grapefruit League game that day for two reasons: They don’t want to overexpose him to the Nationals, whom he’ll face on Opening Day, and they want to take a longer look at less-established starter David Peterson.

deGrom will throw around 90 pitches in his simulated game, then take an extra day of rest between that outing and Opening Day.

Searching for outs

Although Dellin Betances expects to add velocity over the final week of camp, his fastball has gone backwards since his spring debut, when he topped out at 94 mph. That was down to 92 mph on Wednesday, with most of his pitches in the 90-91 mph range. He’s been in that bucket for much of spring.

Consider it notable for a player who once regularly touched triple digits with his dynamic fastball. Betances averaged 94 mph with the pitch last season, but baseball’s disjointed 2020 campaign, combined with a litany of injuries for the right-hander, made that easier to stomach. He’s working this spring on finding ways to record outs with lesser stuff; to that end, he relied more heavily on his curveball against the Cardinals.

“I’ve got to be able to read swings, pay a lot more attention to scouting reports and understand what guys like to do,” Betances said. “In the past, I would rely on the stuff I had. Now, obviously, I’m not there, so I’ve got to mix pitches, change speeds, and I’ve got the confidence in myself that I can get it done.”

Mets cetera

• Corey Oswalt, who started in place of Walker on Wednesday, delivered four innings of one-run ball against a representative St. Louis lineup before being reassigned to Minor League camp; he is likely ticketed for Triple-A Syracuse. Said Oswalt: “I believe in my stuff. I believe I’m a capable starter.”

• The Mets will have a true off-day on Thursday, with nothing happening at their Port St. Lucie, Fla., complex. The break will provide the players with an opportunity to relax in advance of their final four Grapefruit League games. The Mets will then hold a team workout next Tuesday, followed by another true off-day on March 31.

• Those in favor of quick games received a reprieve in the ninth inning on Wednesday, when Bruce Maxwell grounded out against Jordan Hicks to end things. On deck was none other than Luis Guillorme, who drew a 22-pitch walk against Hicks earlier this month.