CHICAGO _ Cubs late-inning reliever Pedro Strop was diagnosed with a meniscus tear of his left knee and is expected to be sidelined from four to six weeks.
An MRI revealed the tear. Strop will have arthroscopic surgery Friday. All of Strop's ligaments were intact.
Strop, 31, posted a 2.89 ERA in 50 appearances and has a lifetime 3.24 ERA in 372 career appearances.
Manager Joe Maddon said Wednesday night that Joe Smith, who was acquired from the Angels an hour before the Aug. 1 trade deadline, would assume more late-inning duties despite the ascent of 24-year-old rookie reliever Carl Edwards Jr.
Edwards has struck out 26 in 19 innings to go with a 1.42 ERA in 18 appearances. He also has limited opponents to a .098 batting average.
