FLEX 12-Team Standard

12-Team standard need some FLEX help

QB: Kyler
WR: Chark, Kupp
RB: Carson, Robinson
TE: Waller
FLEX: DK Metcalf, ________

Options: McKinnon, Damien Harris, Tee Higgins, Justin Jackson

I’m leaning towards McKinnon even if Mostert is back. If Mostert is back should I pivot to Harris or Higgins?