The Rockies made a handful of roster announcements yesterday, including the return of a couple of favorites from happier times in the organization. Yorvit Torrealba, previously with the club from 2006 to 2009, has won the backup catcher’s job over Ramon Hernandez, who will be designated for assignment. The Rockies also have signed Aaron Cook, the winningest pitcher in club history, to a minor league contract. Cook pitched for Boston last season and was waived by Philadelphia this spring. The Rockies also announced that Chris Nelson would start the season at third base, meaning top prospect Nolan Arenado would start the year at Triple-A.