The Colorado Rockies will begin their three-game series against the Pittsburgh Pirates on Tuesday night. The Rockies are not having the best month of May so far. The team has only won two games. Momentum must shift during this series.  Rockies vs Pirates Preview Colorado Rockies starting pitcher Michael Lorenzen | Ron Chenoy-Imagn Images Colorado is entering the series after losing 2 out of 3 on the road against the Philadelphia Phillies. The Rockies got shut out 6-0 on Sunday afternoon. It will be important for the Rockies to make this Pennsylvanian road trip the best possible by winning this series against the Pirates, who are trying to keep their three-game home win streak alive. The Pirates have been a solid team this season.  The Rockies and Pirates met six times last year. The Pirates win four of those meetings. All of those six games were in August.…