"Maybe one of the worst things that could have happened was to have him walk right out and hit a homer on Opening Day," manager Terry Collins said. "As I told him, I just thought he was over-swinging. When he got on base, he was dangerous. He just wasn't getting on."
Cowgill had not started a game in more than a week, losing playing time to fellow right-handed-hitting outfielder Juan Lagares.
Brown, by contrast, was thriving at Triple-A Las Vegas, hitting .367 with two home runs in 25 games, with an .882 OPS against left-handed pitchers. He never received serious consideration to make the Opening Day roster due to his Grapefruit League struggles and Cowgill's strong spring, but Brown has been on fire ever since.
"The report was he's really hitting lefties exceptionally well," Collins said. "We're trying to find some offense in our outfield, so I thought it might be time."
Currently in his seventh professional season, Brown cracked the Majors each of the past two summers with the Cardinals and Rockies, respectively, appearing in a total of 57 games.
"You're getting to go play in the big leagues -- there's nothing better than being here," Brown said. "You don't want to be in Triple-A. You want to be here helping the big club out."
A corner outfielder by trade, Brown also has plenty of history at first base, where he could see playing time for the Mets. He started in right field Friday, batting eighth against Braves left-hander Mike Minor.
"Obviously, I'd probably prefer to take some ground balls here and there ... so I could get used to being in the infield compared to being in the outfield," Brown said. "But I feel like I can do a pretty good job doing it if I'm needed to."
Anthony DiComo is a reporter for MLB.com. Follow him on Twitter @AnthonyDicomo. This story was not subject to the approval of Major League Baseball or its clubs.