Mike Martz brought a hakuna matata mindset to the passing game -- and is now out of the League.
With respect to your question, people understand that passing is inherently riskier. Additionally, a good share of INTs can be viewed as functional equivalents of a punt. That is never the case with a fumble.
I did a study several years ago (unfortunately, I didn't back up my computer, my hard drive crashed, and that data is lost…), looking at several years' worth of numbers. The typical turnover cost a team 59 yards of field position compared to a punt. So let's say you're going to give up the ball anyway - a turnover is much, much, much worse than a punt. Now that's pretty obvious, as even the deepest interceptions still usually occur no more than like 40-50 yards downfield.
According to advancednflstats.com (http://www.advancednflstats.com/2008/08/expected-points.html
), a 59-yard difference in field position produces a point expectancy difference of about 5.5 per possession. Turn it over 3 times like the Patriots did, and we're talking about expecting to give Denver about 16.5 points - and guess what? Denver scored 17 off those 3 turnovers.
Weighing the risk/reward of passing vs. running is a good exercise. Let's compare Brady to Ridley for a moment. Not really a fair comparison because Brady has one of the NFL's all-time best INT ratios and Ridley appears to be kind of a fumble machine. Let's not count QB scrambles, since that's not easy to find in the data.
- Brady: 461 pass plays (430 pass att, 31 sacks), 2695 yards (2896 passing, -201 lost on sacks), for an average of 5.8 yards per pass play. He also has 7 interceptions and 7 fumbles - let's just count 6 fumbles because one came on a designed rush by Brady (that ill-fated QB sneak fumble early in the year). So 13 turnovers in 461 pass plays, for a percentage of 2.8%.
- Ridley: 135 rush attempts, 9 receptions, for 144 total touches, 636 total yards, for an average of 4.4 yards per touch. He has 4 fumbles, for a percentage of 2.8%.
So they have the same turnover percentage, but Brady averages 1.4 yards per play passing more than Ridley does handling the ball. Now, if we apply the -59 yards per turnover, that brings Brady's total yards down to 1928, or an average of 4.2 yards per play. Ridley's total yardage is reduced to 400, or an average of 2.8 yards per play. So factoring this in, it's pretty clear that the risk/reward for the Patriots is to let Brady throw a lot more than giving the ball to Ridley. Of course, that can change if the defense plays a 3-man front and puts 7 guys in coverage all the time.
Obviously if you had a QB that was less capable of protecting the ball, and a RB that was MORE capable of protecting it, maybe the equation changes. But the better percentage play is a Brady pass vs. a Ridley run.