His average fastball velocity has dropped along the way, from 94.3 mph during his stellar 2014 season, to 93 mph in 2015 and 92.1 mph in 2016.
Is he healthy?
"We'll find out," Brewers manager Craig Counsell said. "That's kind of the process."
Teams can request medical records on waiver claims if the player was on the disabled list in the current season, but that was not the case with Ramirez.
"We still think that the stuff has the ability to play at the Major League level," Brewers GM David Stearns said. "Clearly, the velocity is down a little bit. We think there's a chance he can get it back up, and we also think there's a chance that even if it doesn't get all the way up, he can be effective."
Ramirez is the fifth reliever either signed, acquired in a trade or claimed off waivers by the Brewers since the start of April. The others were Carlos Torres (free agent), Sam Freeman and Jhan Marinez (trades) and Michael Kirkman and Ramirez (waivers). Freeman and Kirkman were later navigated to Milwaukee's Minor League system.
The Cubs designated Ramirez for assignment on May 21. To make room for him on Milwaukee's roster, the Brewers designated for assignment Rule 5 Draft pick Colin Walsh.
Ramirez is out of options.
"Great kid, outstanding," Cubs manager Joe Maddon said. "He fit in here really well. If he's able to maintain good health and opportunities, he'll be able to pitch well. He's got a great arm. He's got a wipeout slider. With good health, this guy can be very good and I wish him nothing but the best. If he stays well, he'll pitch well."
Ramirez will wear uniform No. 58 beginning Wednesday. On Thursday, the Brewers will add another relief arm in left-hander Will Smith, who has re-joined the team following a Minor League rehabilitation assignment.
Smith, projected for a critical relief role with the Brewers entering the season, has been on the disabled list with a torn LCL in his right knee. He was able to get back on the mound without surgery, and will pitch with a brace.
"I'm ready. I'm excited," said Smith, who returned without the beard that he had been growing since the date in Spring Training he tore the ligament while taking off his right shoe. "A lot of people told me it went by quick; I disagree with that."
Fellow reliever Corey Knebel (oblique), starter Matt Garza (lat) and outfielder Domingo Santana (shoulder) began rehab assignments on Tuesday. Santana was sent to Double-A Biloxi and could be active as early as Friday.