Will Rockies' depth lead to a trade?

  SCOTTSDALE, Az. – Few expect much from the Colorado Rockies’ pitching staff this season, and understandably so. The Rockies had a 5.49 team ERA in 2012, the worst in the National League by nearly a run per nine innings.   Offensively, though, the Rockies should be a handful for opposing staffs – and they’re deep enough in hitters to possibly swing a trade for another starting pitcher before Opening Day.   Catching is an area of particular surplus for Colorado. Wilin Rosario, Ramon Hernandez and Jordan Pacheco are on the team’s 40-man roster. Yorvit Torrealba is a non-roster invitee to spring training. Hernandez, earning $3.2 million, is likely the one the Rockies most would like to trade.   The team wants to add one more capable starting pitcher, major-league sources say – someone who could throw 150 to 175 innings and produce a ERA in the 4.50-4.75 range. Someone like right-hander Josh Fogg, who pitched for the Rockies in 2006-07.   Even pitchers of such modest quality are difficu