MIAMI -- Add another deal to the busiest in-season transaction month in the Marlins' history. On Monday, Miami announced the acquisition of lefty reliever Donnie Joseph from the Royals in exchange for cash considerations.

The 26-year-old, who attended the University of Houston, has been assigned to Triple-A New Orleans. To make room on the 40-man roster, outfielder Brent Keys was designated for assignment.

Joseph was designated for assignment by Kansas City on June 24. He had made one big league appearance, and it was a rough one, as he allowed six runs in two-thirds of an inning on June 16 against the Tigers.

Joseph made his Major League debut for the Royals on July 11, 2013, and he made six appearances, tossing 5 2/3 scoreless innings.

At Triple-A Omaha this year, Joseph was 1-1 with a 3.86 ERA and one save. In 25 2/3 innings, he struck out 30.

The Marlins have now made 45 transactions in June, the most in franchise history for an in-season month. The previous high was 30 transactions in May 2009.