Mitchell was actually playing well when Marino went down. What killed them was that they started thinking Super Bowl after beating Dallas on Thanksgiving and not putting in the work for the rest of the season. That was 100% on Shula. Had he been let go after that collapse, Jimmy would've been the coach in 1994 and with a team that talented, he could've done something special.
I did mean the season ending injury to Mitchell (like Marino) killed us in 1993, but I can see how what I said could be taken either way. I agree he was playing at a very high level at that point, high enough to be snatched by the Lions as their starter the next season.
Journeyman Steve DeBerg started that classic Thanksgiving game against Dallas after they both were lost for the year, and the rest of the season - I seem to remember he also got beaten up pretty bad the next game against the Giants, but somehow made it through the rest of the year. It just wasn't the same though with him under center.