Lauded for his pinpoint command all spring, Daulton Jefferies suddenly lost control of the strike zone in the second inning of Sunday’s 9-3 A’s victory over the Giants at Scottsdale Stadium. He issued three walks -- which matched his walk total in 13 innings entering the day -- to load the bases with two outs.

Jefferies had been so dominant in Spring Training to the point that it was impossible for the A’s to gauge how he might respond when things don’t go his way. In what was his final showcase as he battles for a spot in the Opening Day rotation, Jefferies showed some mettle that matched his stuff.

Jefferies paused and took a deep breath after taking a quick stroll around the mound after the third walk. He gazed off into the distance and homed in on a random section of the ballpark, something he’s done at times this spring to relax. Four pitches later, Jefferies escaped the jam by finishing off LaMonte Wade Jr on a nasty changeup for a swinging strikeout.

“I put myself in a lot of sticky situations, but I was able to get out of it,” Jefferies said. “That was a big learning experience. I was able to slow it down a little bit and just breathe.”

Major League starting pitchers make about 34 starts in a full regular season. Even the elite arms might only have their best stuff for about two-thirds of a campaign. As the A’s carefully examine their options for the final slot in their rotation, what Jefferies showed on Sunday is perhaps more impressive than the 1.50 ERA he now holds in six Cactus League outings. He showed he can dig deep and find another way to get Major League hitters out.

“Today was a day he had to fight through his stuff a little bit and be composed out there,” A’s pitching coach Scott Emerson said. “He showed a lot of fight today. To be able to pitch without his best stuff and get through five, he did a nice job.”

If this is Jefferies on a limited day, the A’s will gladly take it. He allowed a solo homer to Mike Yastrzemski in the fifth, but he completed five innings and held the Giants to one run on three hits, with four strikeouts and three walks.

At the onset of Spring Training, Jefferies -- Oakland’s No. 4 prospect, per MLB Pipeline -- entered camp as a virtual lock to begin the season at Triple-A Las Vegas. However, a hip injury to Mike Fiers cracked open the door to an Opening Day roster spot, and Jefferies has practically busted through that door with his stellar performance over the past month.

“I think I’ve been as consistent as possible, and that was the big goal coming into Spring Training,” Jefferies said. “Just be consistent. I want them to know who they’re getting on the mound every time they put me there. I’m proud of the way that I handled myself this spring.”

Now comes decision time.

Manager Bob Melvin will gather with the A’s front office for a meeting of the minds in the next few days to determine which pitcher takes Fiers’ spot in the rotation for the start of the regular season, which gets underway Thursday at the Coliseum against the Astros.

Here’s a breakdown of the three candidates, who each left a strong impression to finish camp:

Daulton Jefferies, RHP
Spring stats: Six games (18 innings), 1.50 ERA, 24 strikeouts, six walks.
Final Cactus League start: 5 IP, 3 H, 1 R, 3 BB, 4 K's

Cole Irvin, LHP
Spring stats: Five games (18 innings), 1.00 ERA, 18 strikeouts, three walks.
Final Cactus League start: 6 IP, 1 H, 0 R, 2 BB, 10 K's

A.J. Puk, LHP
Spring stats: Three games (7 2/3 innings), 5.87 ERA, eight strikeouts, three walks.
Final Cactus League start: 4 IP, 1 H, 0 R, 0 BB, 3 K's

Jefferies, Irvin and Puk will travel to Oakland when the team departs Arizona following the conclusion of Monday’s game against the Giants. Barring injuries, the A’s likely have room on the Opening Day roster for just one, and that addition must happen before Thursday.

How will the A’s make their decision?

“There’s some analytics that will play into it. Best matchups, per se,” Emerson said. “Ultimately, everybody will sit down and let it manifest and come together. It’s a great problem to have. We have to make tough decisions, and that’s always good.”

Roster moves
Following Sunday’s game, the A’s announced that infielder Vimael Machín and outfielder Seth Brown were optioned to Triple-A Las Vegas. Though no official decision has been made, Brown’s optioning could mean that outfielder Ka’ai Tom has secured a spot on the Opening Day roster. Tom, who the A’s selected in the Rule 5 Draft in December, was in competition with Brown for the club’s fourth outfield job.

Up next
The A’s wrap up their Cactus League schedule at Hohokam Stadium in Mesa, Ariz. with a 12:05 p.m. PT game against the Giants on Monday. Left-hander Sean Manaea takes the mound for a final tuneup before the regular season. Right-hander Logan Webb will start for San Francisco.