16 team full PPR... go after Thielen?

My team:
QB Newton, Goff
RB Cook, Michel, K Johnson, R Freeman, R Jones

WR Hopkins, K Allen, Godwin, Callaway

TE Seals-Jones, Thomas

Start 2 RB, 2 WR, 1 Flex

Thielen owner is thin at RB, maybe not as bad as me… but they are deep at WR. They have interest in Kerryon or Cook. Both RB have their issues, Cook health and Kerryon gives way goalline to Blount and catches to Riddick, is it better to land Thielen at flex as a sure thing and unload cook or kerryon and a callaway? This league everyone nabs 2 QB’s, TE’s and such… no waiver wire guys to stream and wondering if Thielen as a sure thing flex versus trotting out what I have and gamble with Michel, Freeman, Cook or Kerryon at RB?