The Brewers called up Frelick from Triple-A Nashville before their game against the Atlanta Braves. They made room by designating Tapia, who batted .173 with a .267 on-base percentage, two homers, three RBIs and two steals in 20 games.
Tapia, 29, signed with the Brewers on June 14 after the Boston Red Sox released him. He hit .264 with a .333 on-base percentage, one homer, 10 RBIs and six steals in 39 games with Boston.
Frelick, 23, batted .247 with a .333 on-base percentage, two homers, 18 RBIs and eight steals in 40 games with Nashville. He missed much of the season after undergoing surgery on his left thumb.
He batted .331 with a .403 on-base percentage in 119 games last season for High-A Wisconsin, Double-A Biloxi and Nashville.
The Brewers selected Frelick out of Boston College with the 15th overall pick in the 2021 amateur draft. He has shown an ability to play all three outfield positions while in the minors.
Frelick's promotion comes as Braves right-hander Allan Winans prepares to make his big league debut Saturday. Winans, who turns 28 on Aug. 10, got the start after going 7-3 with a 2.81 ERA with Triple-A Gwinnett in 18 appearances, including 13 starts.
Frelick will become the eighth player to make his major league debut for the Brewers this season. The others are pitchers Gus Varland, Clayton Andrews and Abner Uribe, outfielders Joey Wiemer and Blake Perkins and infielder Andruw Monasterio.