Here's a quick addendum to my earlier post. 40 passing attempts is an arbitrary and useless description of "carrying your team". I would suggest that a game in which your defense allowed at least 25 points is a better standard. Why? It's arbitrary. 25 points is a lot of points, and represents the kind of game that a QB is going to have to do super work to win. So, just for comparison, I've tracked Peyton Manning and Tom Brady in all games in which their defense allowed 25 points or more to see who did a better job of "carrying the team" when they really needed it. I apologize for not being able to screen out defensive scores, a project of that magnitude is beyond what I can offer right now...
61 times in his career (including the playoffs) his defense has given up at least 25 points. That represents nearly 4 full NFL seasons. Roughly 32% (just shy of a third) of the total games in his NFL career, his defense gave up 25 points or more. The Colts averaged 25.6 ppg, and their opponents averaged 31.7 ppg. The Colts went 20-41 in those games (.329). 1/6 (11 games) of the games came in his rookie season of 1998. After that year (the Colts went 1-10 in those games), the Colts went .380 (19-31) in such games.
Manning went 1393 for 2239 (on average 23 for 37, 62.2%), for 16,620 yards (272 ypg, 7.4 YPA), 112 TD, 74 INT (1.8:1.2 ratio), and a rating of 87.8
32 times in his career (including the playoffs) his defense has given up at least 25 points. That represents 2 full NFL seasons. Roughly 24.4% (just shy of a quarter) of the total games in his NFL career, his defense gave up 25 points or more. The Pats averaged 26.1 ppg, and their opponents averaged 30.1 ppg. The Pats went 14-18 in those games (.428).
Brady went 721 of 1165 (61.9%), for 8255 yards (258 ypg, 7.1 YPA), 60 TDs, 41 INTS (1.9:1.3 ratio), and a rating of 85.7.
It's basically a wash. Manning's numbers are a little better, but they are basically the same as Brady's. After Manning's rookie year, the difference in win percentage is slightly in Brady's favor (extrapolated over 50 games, Brady would have won 21 games to Manning's 19). Neither the difference in stats nor in win percentage are very significant.
So when it comes to "carrying a team" you could basically say that Brady and Manning are about the same using this measure. To figure out if their performance is particuarly good or bad, you'd have to compare it with a list of other QBs. If anyone knows of a way to do that...please let me know.