Manager Buck Showalter wanted to add another lefty to his bullpen, relievers Brian Matusz and Randy Wolf were expected to be unavailable for Monday's series opener against the Blue Jays.
"Our plan was to bring in Zach anyway, but especially because Brian should be down today," Showalter said.
Phillips appeared in 42 games at Norfolk, going 2-2 with a 3.17 ERA over 54 innings. The 25-year-old has logged 8 2/3 innings at the big league level over parts of the past two seasons.
Showalter wants to stay away from Matusz, who has appeared in three consecutive games entering Monday. Since rejoining Baltimore as a reliever, Matusz has allowed one run over 4 1/3 innings while striking out six and walking one.
"He has done a good job. It's not one of those, 'I told you so, that's what we thought all along,'" Showalter said about Matusz's transition to the bullpen. "You look at his numbers, Minor Leagues and Major Leagues, and you know that he is capable of it.
"I know he's enjoying himself. He likes the idea of coming to the ballpark everyday and being engaged about having the chance to pitch and help the club."
Berken, meanwhile, appeared in one game with the Orioles this season, allowing seven runs -- two earned -- in one inning of work. The right-hander spent parts of the past four seasons with the Orioles.