The right-hander is 1-2 with a 5.31 ERA in 45 games. He last pitched on September 7, when he allowed four runs on four hits, including a home run, in one inning of work. Riske has pitched for four other teams -- Cleveland, Boston, the Chicago White Sox and Kansas City -- during his nine-year big league career.
The Brewers may get a boost in the bullpen with the addition of pitcher Yovani Gallardo, who has been out since tearing cartilage in his right knee on May 1. Gallardo pitched a simulated outing against minor leaguers in Arizona and could rejoin the team shortly.
General manager Doug Melvin said that Gallardo is scheduled to pitch two simulated games, but if everything goes well, the Brewers could bring him up sooner, perhaps in time for their series-opener Friday in Cincinnati. Melvin said Gallardo is likely to be used out of the bullpen, although a final decision hasn't been made.
Milwaukee also announced that left-hander Manny Parra was being dropped from the starting rotation in favor of righty Seth McClung. Right-hander Dave Bush is being moved up a day and will start Thursday's series-finale against the Cubs on three days rest. McClung will start on Friday.