Gregory Polanco is headed to the majors. The Pittsburgh Pirates called up their coveted outfield prospect late Monday night after placing second baseman Neil Walker on the 15-day disabled list. Walker experienced abdominal pain shortly before Pittsburgh's 6-2 win over the Chicago Cubs and underwent an emergency appendectomy. Read more http://espn.go.com/mlb/story/_/id/1...-prospect-gregory-polanco-replace-neil-walker
