Cross Ryan Fitzpatrick with Tony Romo and you might just end up with Dave Krieg.
Like Romo, Krieg rose from the bottom of the bench to have some fabulous seasons, as well as some not-so-fabulous ones. Like Fitzpatrick, Krieg played for so long that his origin story became a broadcast trope, and he often played just well enough to get his next job rather than keep his current one. Krieg finished in the top 10 in DVOA five times during his neverending career, yet he always seemed to be just one slump away from a seat on the bench.