Gregg will report to the Marlins' complex in Jupiter, Fla., to throw some bullpen sessions and face live competition before he receives an assignment. There is no timetable for his arrival in the big leagues, but it could be as early as 10 days from now.
By signing a Minor League deal, the Marlins do not have to create an immediate 40-man roster spot for Gregg. But the 35-year-old is not expected to be in the Minors very long.
With the Cubs last season, Gregg saved 33 games in 38 chances and had a 3.48 ERA.
"As we've seen, it's not easy for young guys to [pitch in late innings]," manager Mike Redmond said. "It definitely is an art and comes with the experience. To have Gregg, who's saved a ton of games in the big leagues and has done lots of different roles and has that experience, hopefully will help us down the road."
Gregg's signing marked the second move made by the Marlins' front office since Carter Capps was placed on the 15-day disabled list with a right elbow sprain last week. Dr. James Andrews will evaluate the reliever on Wednesday, and Tommy John surgery is a possibility.
Acquiring experience is important to the Miami ballclub, as it has struggled to hand the ball over to closer Steve Cishek. With Gregg in the bullpen, Redmond would have another potential closer to add to the mix.
"I think if you look at what he's done in his career, he's definitely that guy," Redmond said. "He's closed games, he's done a lot of different roles."
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter