Brantly, 23, started on Opening Day for Miami, and he was being groomed to be the catcher of the future. But after having his rough times at the plate and on the field, his playing time was limited behind Jeff Mathis.
At New Orleans, he will play regularly.
Hill, meanwhile, is making his first start on Sunday in the series finale against the Braves at Turner Field.
"No matter what position you're playing, this is a tough level to learn at," Hill said. "Kudos to the guys who can. I wouldn't look at it as a bad thing for [Brantly] going down there and getting some time in. A million other guys have had to do that, too. I don't think it's a personal attack on anything that he does. I think it's just part of the process."
Hill's first start as a Marlin allowed Mathis to take a breather.
It is Hill's 315th game in the big leagues, and he's seen all sides since he broke in with the Dodgers in 2003.
In 2005, Hill was the D-backs' Opening Day starter, catching former Marlin Javier Vazquez that day.
From 2007-12, he played for the Cubs.
The Marlins are counting on Hill being a capable backup to Mathis. They are looking more for him to handle a young pitching staff than be a big producer at the plate. He has a .211 career batting average.
On Friday night, in a 5-0 loss at Atlanta, Hill caught one inning, and he got a single in his lone at-bat.
So, he got brief playing time with his new teammates.
Developing catchers, he says, is a "process."
"I went to the big leagues in 2003," said Hill, "and I didn't feel like I was confident in what I was doing behind the plate until like 2006."