The DL move for Cabrera, who suffered a sprained left thumb May 6, was retroactive to Sunday. In addition, closer Jeurys Familia, who may miss the remainder of the season after having surgery to repair a blood clot in his pitching arm, was moved to the 60-day DL.
Ramirez, who elected for free agency after being designated for assignment by the Toronto Blue Jays on Sunday, has a 8.71 ERA and 18 strikeouts in 10 innings this season for Toronto and the San Francisco Giants.Ramirez signed a contract calling for a $750,000 salary in the major leagues and $150,000 in the minors.
"Looks like he's got a good arm and some experience, so we certainly are in need of a guy that can come out of the bullpen," manager Terry Collins said.
The Mets' bullpen gave up eight runs in two innings Sunday to squander a 7-1 lead, and then gave up six runs in the eighth inning Monday as the team's losing streak was extended to five games.
Overall, Mets relief pitchers have a 5.26 combined ERA -- fourth-worst in the major leagues.
Collins said his conversations with pitching coach Dan Warthen of late regarding his staff have been "ugly."
"We throw out a lot of stuff, and ultimately they've got to make pitches," Collins said. "That's what it's all about. We've had situations where we've tried to hand out instructions on how to go about things, and it's got to get executed."
New York relievers have given up seven homers in the past five games and compiled a 13.80 ERA over 15 innings.
The Mets will be the sixth team for Ramirez, 27, over the past two seasons. He pitched for the Cubs, Brewers and Twins last season and has a 3.72 ERA over four seasons.
Ramirez's deal with the Mets calls for performance bonuses of $25,000 each for 30 and 40 relief appearances.
As a rookie in 2014, Ramirez pitched 50 games for Cubs, going 3-3 with three saves and a 1.44 ERA.
Cabrera has not played since aggravating a thumb injury last Saturday in Milwaukee. He is batting .257 with three home runs and 14 RBI.
In other news, the Mets plan to skip struggling rookie Robert Gsellman the next time through the rotation. In his place, Jacob deGrom will start on his regular four days of rest Friday night at home against the Los Angeles Angels.
Gsellman will move to the bullpen for now. The right-hander is 2/3 with a 7.06 ERA in seven starts and one relief appearance this season.
New York is off Thursday and next Monday, giving the team a chance to tweak its rotation while still keeping its other healthy starters on full rest.
The Associated Press contributed to this report.