I still would LOVE to see Rosen play well enough this year to give the Dolphins a comfort level to pass on a QB in 2020. If we lose a lot this year, deal away that high draft pick for massive 2021 assets. Use the considerable remaining draft assets & cap space in 2020 to build the lines.
Roll with Rosen in 2020. If it works out well, great news. If it doesn’t, use everything you received from trading that high 2020 draft pick, plus whatever else it takes to get Lawrence (assuming the team picking #1 in 2021 will even consider dealing).