He's so overrated. He needs talent to field a great defense? Well he had Urlacher, Peppers, and Tillman in Chicago from 2009-2012 and here are Rodgers stats against the Bears in 8 regular season games:
15 TDs, 4 INTs
249 yards/game
68.69% completion
102.41 QB rating
7-1 record
^that is the BEST he can do against Aaron Rodgers. Now the Bears did defend Rodgers pretty well in their one playoff game in 2011 (17-30, 244 yards, 0 TDs, 2 INTs) but that was the only game and it was in bad/freezing weather, if I recall correctly.
I also looked up how well Marinelli did vs. some other elite QBs during his time in Chicago:
Tom Brady in 2010: 27-40, 369 yards, 2 TDs, 0 INTs
Drew Brees in 2011: 26-37, 270 yards, 3 TDs, 0 INTs
So even given a defense with better talent, that is usually the best his defenses can do against elite QBs.