Brian Serven joins the Colorado Rockies amidst a series of transactions; Bryant and Senzatela injury updates

After dropping to one game under .500 for the first time since an Opening Day loss to the Los Angeles Dodgers, the Colorado Rockies’ roster is undergoing a few changes this week. The most intriguing move on Tuesday was the one made out of choice: the club’s backup catcher.  Dom Nuñez was optioned to Triple-A Albuquerque and Brian Serven was…