Johnson spent two seasons with the Philadelphia Eagles and one season with the Houston Texans where he was ahead of current Patriots wide receiver Keshawn Martin in the depth chart. The 5'7, 170 lbs Johnson is a great option in the slot and he offers value as a returnman. The Patriots next two games are, coincidentally, against the Eagles and the Texans.
The Patriots will place Johnson in the depth chart behind Brandon LaFell, Danny Amendola, and Keshawn Martin. Johnson will provide insurance for Amendola and shouldn't see much time on the field.
Harper was released to make space for Martin in September, when the receiver was acquired from the Texans. Harper's name plate is still on his locker and is expected to return to the practice squad.