MESA, Ariz. -- A’s catcher Chris Herrmann went through with arthroscopic right knee surgery Friday, the results of which will help determine just how long he’ll be sidelined.

Dr. Doug Freedberg, based in Scottsdale, performed the procedure, which was expected to address a fissure and loose bone spurs.

The A’s, meanwhile, are sorting through the details of their backup plan behind the plate. Right-handed bats Nick Hundley and Josh Phegley are expected to share catching duties during Herrmann’s absence.

“We’ll try to figure out what we think the best matchup is on a particular day,” A’s manager Bob Melvin said. “Nick has had some knee injuries before, so I don’t target him as a guy I feel like could play every day, so I think it might be a pretty even split to an extent as we sit here right now.”

Both are hitting the ball well this spring. Hundley is 5-for-17 with three extra-base hits. Phegley, who homered Friday in Oakland's 6-5 victory over the Padres, has seven hits in 20 at-bats for a .350 average.

Phegley, entering his fifth season with the A’s, is out of Minor League options and was in danger of losing his roster spot had Herrmann not gone down.

“I think this is a great opportunity for him,” Melvin said. “I think the second half of last year, he finally kind of acclimated to the role he was in and played really well. You look at the record, which I look at it, when he was in the game, and he won a lot of games when he caught.

“I don’t think he ever wants to say, ‘Hey, look, I’m a backup,’ but I think he did a great job last year acclimating to that role and preparing for it, and a lot of that is mental.”

A’s sorting out pitching plans

Melvin has yet to reveal his starters for the club’s two-game Opening Series in Tokyo from March 20-21, but an announcement could come soon.

Veteran right-handers Mike Fiers and Marco Estrada are the favorites to pitch against Seattle. To this point, they’ve been on the same schedule this spring. On Friday, Estrada started against the Padres, while Fiers -- considered the favorite to pitch on Opening Day -- got in his work in during a simulated game at the Minor League facility.

Estrada went three innings, allowing three runs on three hits and two walks with one strikeout.

“Today wasn’t me,” he said. “I was having trouble locating my pitches, even my changeup, which is my go-to. Just getting a feel for it again. The good thing is, I feel good stamina-wise. I could’ve kept going, but Spring Training we’re getting our work in.”

The race for the final rotation spot also continues on, and top prospect Jesus Luzardo -- who has made all of four starts at the Triple-A level -- is still in consideration. Luzardo has yet to allow a run this spring and will make his next start Sunday at home as part of split-squad action against the Giants in the team’s lone televised game of the season.

“With everyone pitching so well, it’s going to make our decisions that much tougher, and we don’t have that much time left,” Melvin said. “They’re making it tough on us, for sure.”

The A’s break camp and depart for Tokyo on Thursday.