"We're going to be able to expose some players for evaluation and get guys more acclimated to the Major Leagues so they're not in awe," Black said. "The experience is invaluable for players with lesser service time. And they can help us win games."
Layne, 28, is in his fourth stint with the Padres this season. He's appeared in nine games, going 0-2 with a 2.45 ERA and six strikeouts against two walks. The Padres were short in the bullpen after optioning Anthony Bass to Triple-A on Saturday to clear room for Kyle Blanks' return from the disabled list.
"It made sense to get another arm here when we could," Black said.
Robinson, 29, had a brief stint with the Padres two weeks ago but did not appear in a game. He will make his Major League debut soon.
"It's great for him to get exposed to September," Black said. "He'll get in a Major League game. He's been a guy that has been through the trials and tribulations of a Minor League season. It's great to have him be part of a Major League team."
Bass will likely return to the Padres as early as Tuesday. Bass, Boxberger and Brach were each optioned to Triple-A last week, and are eligible to return to the Majors after Tucson's season ends on Monday.