Just traded Cordarelle Patterson for David Montgomery...was that dumb?

12 Team, 2 Flex PPR league

RBs are Zeke, Henderson, Gaskin, ROJO, McKissic…and now Montgomery
WRs are Diggs, Lockett, AB, Shepard, Mooney, Claypool
TE is Waller

Had Patterson in the 2nd flex and felt kind of good about it this week with the Falcons injuries and facing the Jets. Been hearing a lot about trading Patterson high though…is buying an injured Montgomery not selling high enough, or good plan for the future?