OAKLAND -- While the A's had a day to forget on Saturday, rookie catcher Kyle McCann did his best to soak everything in as he made his long-awaited big league debut. There's one memory in particular that he believes will stand the test of time.

"Honestly, it's putting on the ol' white uniform," he said. "That one kind of sank in for me. I've always liked the look of it, so I felt swaggy."

After breaking camp with the A's to make his first Opening Day roster, McCann made his Major League debut in front of family and friends in Oakland's 12-3 loss to Cleveland at the Coliseum.

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Entering the 2023 season, the 26-year-old backstop had been one of the leading candidates to crack the A's roster as the backup catcher, but veteran Carlos Pérez ended up winning the job instead. McCann spent the entire year with Triple-A Las Vegas, hoping to play his way onto the big league club's radar.

"I had some expectations to make the team out of last year's spring, but I didn't. … There were some times that I thought I might be called up [last year], but at the end of the day, it didn't happen," McCann said. "But this year is a different year. And now that I'm here, I'm ready to go."

A fourth-round selection out of Georgia Tech in the 2019 MLB Draft, McCann played four seasons in Oakland's farm system -- not including 2020, a lost year for most Minor Leaguers due to the COVID-19 pandemic. He put together his best overall offensive season with Las Vegas in the hitter-friendly Pacific Coast League in '23, slashing .270/.351/.474 with 17 homers, 17 doubles and 57 RBIs.

Though McCann is still seeking his first Major League hit after going 0-for-2 with two strikeouts on Saturday, he got a couple of milestones out of the way, including scoring his first run and notching an RBI, before recording an official at-bat.

McCann showed off a selective eye in his first two trips to the plate, drawing a pair of walks against Guardians right-hander Tanner Bibee, the runner-up in AL Rookie of the Year voting in 2023. He scored on Ryan Noda's RBI single in the second inning, then took a bases-loaded walk to force in what was then the go-ahead run in the third to give Oakland its first lead of '24.

Of the 21 pitches McCann saw, he swung at only three located outside of the zone.

"I was just trying to get a pitch that I could handle," McCann said, "And if it wasn't there, I was telling myself to take it."

McCann had a tougher time behind the plate, as the Guardians were aggressive on the basepaths and swiped six bags against the rookie catcher. McCann also made a throwing error while attempting to throw out Gabriel Arias in the fourth, an inning where Cleveland plated three runs to take the lead for good and chase Oakland starter JP Sears.

"I thought he caught a great game, just got to do some better execution," said Sears, who allowed five runs over 3 2/3 innings in his season debut. "Stuff between us two will continue to get better, and whoever he works with, but he had some great at-bats early in the game. So super proud of that for him."

Manager Mark Kotsay, though, said the A's pitching staff needed to do a better job of controlling the Guardians' running game.

"Our times to the plate were bad," Kotsay said. "They didn't give Kyle really any opportunity to throw anybody out. Obviously, they ran on us all day and we've got to address that."

Aside from a highlight reel-worthy home run robbery by JJ Bleday in the first inning, the A's didn't have much going their way as they dropped to 0-3, their worst record to open a season since losing six straight to begin 2021.

McCann, regardless, heeded his dad's advice to enjoy every moment -- after all, he only gets one Major League debut. He was able to make the most of the day, even though the ultimate outcome was disappointing.

"I maybe would've wanted a hit, but that's the probably the only thing I would have expected, but I had an awesome time. It was super fun," McCann said. "Obviously, I also wanted to win a game."

The A's, too, are hungry to get in the win column for the first time in 2024.