In a corresponding move, the club designated right-handed relief pitcher Vinny Nittoli for assignment to make room for Uelmen on the 40-man roster.
Uelmen, 26, had been designated for assignment by the Cubs on December 24.
Uelmen made 25 appearances in relief for the Cubs last season, compiling 27.0 total innings in his first year in the majors after Chicago called him up from Triple-A Iowa in July.
Uelmen racked up a 4.67 ERA and 1.370 WHIP across his 25 appearances, striking out seven and walking four per nine innings. He largely uses a four-seam fastball, a sinker, and a slider according to Statcast, with a changeup making an appearance 8.9% of the time. His fastball averaged 93.7 miles per hour last season.
Assuming he heads to Clearwater next month, Uelmen will be battling for a 40-man roster spot in the bullpen with familiar faces like Sam Coonrod, Nick Nelson, and maybe Christopher Sanchez, along with prospect Andrew Baker. There's also the question of where Bailey Falter lands on the roster, whether it's in the starting rotation or in the bullpen.
The Las Vegas native was drafted in the fourth round of the 2017 MLB Draft out of Cal Poly San Luis Obispo.