PHOENIX (AP) -- Brewers starter Yovani Gallardo will leave Monday for Milwaukee to undergo a left knee scope on Tuesday. The promising young pitcher has a lateral meniscus tear and is expected to miss four weeks

Brewers spokesman Tyler Barnes said Sunday the right-hander had discomfort a few days ago after a throwing session. His knee swelled up afterward, and the team was concerned he might have a cartilage tear.

Head team physician, Dr. William Raasch, examined Gallardo on Sunday and will also perform the knee scope on Tuesday.

The 22-year-old Gallardo, expected to be a main cog in the Brewers rotation, was 9-5 with a 3.57 ERA in 20 games last season, including 18 starts.

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