OAKLAND -- If Brandon Marsh's big-league debut on Sunday was defined by jitters, his second game was an exhibition of potential.

Marsh, the Angels' No. 1 prospect per MLB Pipeline, recorded his first, second and third career hits in the team's 4-1 loss to the A's on Monday at Oakland Coliseum, the last of his base knocks being an opposite-field double in the ninth inning that kept Los Angeles from being blanked.

"Definitely a lot of weight lifted off the shoulders," Marsh said. "It was a great feeling."

• What to expect from Brandon Marsh

Marsh went hitless in four at-bats in his first game, but he was more than happy to have experienced the moment, describing it as "everything that I kind of dreamed of and expected." With the pomp and circumstance gone upon arriving in Oakland, Marsh got down to the business of proving that he belongs.

The outfielder didn't waste any time in his first at-bat in Oakland, lining a single to right-center field to give himself a big-league batting average. The A's were well aware of the milestone and promptly tossed the ball back to the Angels' dugout, which celebrated the occasion with a parade of applause.

The lasting image of Walsh's first career hit will be his helmet flying off as he pulled into first base despite there being no need, allowing his shoulder-length hair to flow with the wind.

"There's a calmness about his game," said manager Joe Maddon. "You could see it, even from a distance. Fluidity, calmness, never really in a hurry."

Marsh's season got off to a rocky start, as he missed the first month and change due to a labrum issue, then missed nearly all of June due to a shoulder injury. Upon returning to Triple-A Salt Lake from the latter ailment, Marsh hit the ground running, going 13-for-34 (.382) in eight games with a hit in each contest.

Playing time might be trickier to come by for Marsh as Mike Trout (right calf strain) and Justin Upton (lower back tightness) work their way back from their respective injuries. In the meantime, however, Marsh will have ample opportunity to establish himself at this level.

"If you're a scout, you're out there watching this kid for the first time, the way he moves is just going to turn you on," said Maddon. "You're just going to say, 'Wow.' You watch him swing the bat, you watch him run, his arm looks like it's playing pretty well right now. Here's another guy with a high baseball IQ."

Upton's rehab off to booming start
Upton's rehab assignment with Triple-A Salt Lake is off to a great start, as the outfielder launched the very first pitch he saw on Monday for a no-doubt solo home run.

"He did that several times for us, too, so he's kind of gotten used to it," Maddon said.

Upton hasn't played for the Angels since June 22 as he recovers from lower back tightness. The injury came at an unfortunate time for Upton, who slashed .338/.463/.631 in June with four home runs.

"He'll play again today and then we'll re-evaluate after that, just see how he felt, where he's at, what we all think, and then we'll make our determination," Maddon said.

Worth noting
• Trout made the latest progression in his recovery process, running around the bases prior to the Angels' game on Tuesday.

"So much we take for granted," Maddon said. "Something as simple as running the bases, but there's so many things going on in that movement. And when you get injured, you have to check all those boxes."