Despite the lack of a police report detailing the incident, MLB and the union agreed the allegations against German warranted placing him on seven-day leave amid an investigation, sources said.
The investigation is expected to be fast-tracked, and German could face discipline from MLB -- including a potential suspension -- before the Yankees host Game 1 of the American League Division Series on Oct. 4, sources told ESPN.
"We fully support all measures being undertaken by the Commissioner's Office pursuant to the Policy on Domestic Violence," the Yankees said in a statement. "We support this policy which reinforces that domestic violence has no place in our society and cannot be tolerated.
"We have followed the lead of Major League Baseball and will continue to provide our complete cooperation throughout the investigative process."
MLB and the Yankees said they would have no further comment until an investigation has been completed. Under the joint domestic violence policy, a player can be put on administrative leave for up to seven days, barring a mutually agreed-upon extension between the league and union.
German, 27, pitched Wednesday for the Yankees. He is 18-4 with a 4.03 ERA and 153 strikeouts. The emergence of the right-hander, who has been by far the Yankees' most reliable starter, has helped mitigate the struggles of veterans in the rotation.
Manager Aaron Boone recently said he expected German to be a big part of the team's postseason plans, but Boone said Thursday that the team needs to prepare for the postseason like German won't be available.
"This is something that, baseball aside, this is a bigger issue, obviously," Boone said. "When you hear the words domestic violence, it's one of those things that stops you in your tracks. I give Major League Baseball and the players' association credit for doing their part in, several years ago, trying to be ahead of this and putting disciplinary action in place, hopefully being part of the solution to what is a problem in our society."
Boone and general manager Brian Cashman spoke with players before Thursday night's game.
"It's a difficult situation that none of us really know that many details about, so you just try and lay it out,'' Boone said. "Sometimes things come up over the course of the season that you're not necessarily prepared for and you just try and talk through it the best you can.''
Luis Severino returned to the rotation Tuesday, making his 2019 debut. However, the team lost reliever Dellin Betances for the remainder of the season after he tore the Achilles tendon in his left foot Sunday.
The Yankees called up right-hander Michael King to take German's spot on the active roster.
ESPN's Marly Rivera and The Associated Press contributed to this report.
Passan: German could be suspended for postseason
Jeff Passan believes Domingo German is likely to face some disciplinary action, perhaps even a postseason suspension.