Duarte had his contract selected from Triple-A Louisville by the Reds on Tuesday.
Duarte will join the Reds in Kansas City ahead of the second contest of their three-game series with the Royals. The right-hander has produced a 3.49 ERA and 1.28 WHIP with 32 punchouts over 28.1 innings in 26 appearances with Louisville this season, and he'll slot in as an additional bullpen arm with Cincinnati. In order to make room on the 40-man roster for Duarte, Joel Kuhnel was designated for assignment Tuesday while Ricky Karcher was optioned to Triple-A to make space on the major-league roster.