In fairness, Poyer has looked like he’s running through quicksand at times this season. I don’t think the drop off in speed will be noticeable (ie, Tyreek would blow past either of them if we don’t bump him - or tackle him - off the line).
This game will be won/lost by the Dline and LBs and how much pressure they can get on Tua. There will be at least one or two huge pass plays by Miami; that can’t be stopped completely. But a few shots to Tua could really get in his (mushy) head.