A promotion to Class AAA two weeks ago once seemed destined to be the highlight of Brandon Bantz’s season.

But then came a Tuesday night phone call telling Bantz that because of injuries and serious catching depth problems the Mariners have, his major-league debut was about to be accelerated. That was the case Wednesday morning, when the Mariners added the unheralded, 30th-round draft pick from 2009 to the big-league squad to fill in a few days while Jesus Sucre nurses an injury.

“It’s a real surreal experience still,’’ Bantz said Wednesday after arriving at Safeco Field and being assigned a locker. “It still feels kind of surreal at the moment. I’m real excited. It’s my lifelong dream.’’

Surreal indeed, since Bantz had played only three games at the AAA level this year after starting off for 14 games with AA Jackson. His name rarely surfaces when discussions about future Mariners catchers comes up, and he even spent time in the Australian Baseball League at one point.

The Mariners optioned infielder Carlos Triunfel to AAA make room for Bantz on the big-league squad and added Franklin Gutierrez to the 60-day DL to clear a 40-man roster spot.

In opting for Bantz, 26, the Mariners also left No. 1 draft pick Mike Zunino at AAA, citing concerns about possible harm to his catching development.

But since the move is likely only to be for a few days, it’s possible other issues besides development are also driving this choice. Calling up Zunino now and then returning him to AAA would burn one of his three minor-league option years for the sake of just a few games.

The options won’t matter if Zunino becomes a solid big-leaguer right away. But with the recent struggles of Dustin Ackley, Jesus Montero and Justin Smoak — all optioned to AAA at one point over the past year — it’s possible the team wants to keep future options open for Zunino just in case.

There is also the matter of “Super 2” status and Zunino potentially qualifying for arbitration a year early if he gains enough service time to be among the top 20 percent of new players two years in. That could be mitigated, of course, if the team simply sent Zunino back to AAA after a short call-up and then held him in the minors a few extra days longer to compensate.

But again, that would require burning an option year.

So, now, the team has Bantz, who manager Eric Wedge pretty much says will only be backing up starter Kelly Shoppach the entire time he’s here.