Mets closer Jeurys Familia left Tradition Field before Friday's workout and returned on Saturday morning, only to leave again, according to Marc Carig of Newsday.
Manager Terry Collins told reporters that Familia will also miss Sunday's workout and he will not return until Monday.
Familia was originally expected to return on Saturday, but he will miss workouts for a second consecutive day due to MLB's investigation into his domestic violence arrest, reports Mike Puma of the New York Post.
Earlier in the day on Friday, Collins said Familia left camp due to personal reasons.
According to eyewitnesses, he had a brief exchange with Sandy Alderson before leaving the clubhouse on Friday.
The investigation into his domestic violence incident from last October is still ongoing, though MLB expects to make a decision regarding a potential suspension before Opening Day, commissioner Rob Manfred said the last week of January, according to Dave Lennon of Newsday.
Familia is expected to be suspended at least 30 games to start the season, despite having all charges dropped against him, sources told Daily News reporter Kristie Ackert in December.
He told reporters after arriving to Tradition Field earlier this week that he has been advised by his lawyer and the team to not discuss incident.
Mets relievers Jeurys Familia and Addison Reed (Credit: USA Today Sports Images)
"I think you've got to be smart enough to realize there probably is going to be some type of penalty," Mets manager Terry Collins said Monday, when asked about Familia's status. "I don't know what it is. I have no idea yet. So I think you've got to go into this right now making sure that Addison Reed is ready to pitch the ninth inning starting the season. Familia, we know he'll be back sometime. But we've got to get our bullpen in shape in case he's going to be gone for a period of time."
In 78 appearances for the Mets in 2015, Familia had a 2.55 ERA (2.39 FIP), a 1.21 WHIP, and 84 strikeouts in 77 2/3 innings, while saving a team-record 51 games. He will earn $7.4 million this season. He is eligible for arbitration in 2018, after which he will be a free agent.
In 80 appearances for the Mets in 2016, Reed had a 1.97 ERA and one save, while striking out 91 batters and walking just 13 in 77 2/3innings pitched.