The 49ers have promoted practice-squad wide receiver Chris Harper and made room him on the 53-man roster by releasing running back DuJuan Harris before tonight’s season opener against the Rams. In 2015, Harper, an undrafted free agent, spent most of his first NFL season on the Patriots’ practice squad. Harper, 22, was on the 53-man roster for five games and had one catch for six yards and three punt returns for 17 yards.