Morse was brought in for his bat, with the Giants needing an upgrade in production out of left field. But with Morse's defensive shortcomings, Perez could fit as a late-inning defensive replacement, though Saturday brought added competition.
The Giants are likely to break camp with five outfielders. Angel Pagan and Hunter Pence are locks to roam center and right; Morse figures to get the majority of starts in left; and Gregor Blanco should be one of the first reserves off manager Bruce Bochy's bench.
The 27-year-old Perez, who spent the past five seasons in the Giants' system and is in his fourth big league camp, entered Spring Training considered the favorite to be the fifth outfielder.
"I'm aware of that, but I have to be ready and do my job," Perez said Saturday morning. "I have to hit the ball when I'm up and catch every ball I can when I'm in the field. I have a lot of chances, I think. I just have to do my job, take advantage of the opportunity I get playing-wise on the field."
Roger Kieschnick, known more for his bat than his glove, appeared to be Perez's top competition until the Giants signed Tyler Colvin to a Minor League contract early Saturday.
"It's not certain we'll go with five outfielders, [but] that's where we're leaning right now," Bochy said. "Ideally, you'd take a guy who's versatile, with the bat and defense. ... A lot of it will be determined by who we're playing and the game situation. On the whole, we definitely need a guy who is going to give us some defense."
The field is where Perez made his mark with the team a year ago and where he holds an advantage over the competition. Perez made a handful of highlight-reel catches in both left and center during his 34 games with the Giants.
But Perez hit just .258 with a .650 OPS during that late-season stint, and is a career .279 hitter in the minors.
"They know what I can do in the field," Perez said. "I take a lot of pride in that because I work hard on it."
At the plate, Perez said he wants to take the ball to the opposite field more often as well as drive it into the gaps.
Before news of Colvin's signing got out, Perez said he wasn't going to worry about any competition.
"This year is going to be different because last year I played in the big leagues," Perez said. "I just have to take what I did at the end last year and bring it over to this year."
Chris Gabel is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.