Preseason stats aren't the most meaningful, but here's a look after 2 games.
Starting with the backup QB battle, leader in each category bolded
*=Adjusted Net Yards Per Attempt (the best QB stat you can get from boxscore info):
(passing yards - sack yards - 40 x INT +10 x TD)/(pass attempts + sacks)
So even with the two picks Gray's ability to get the ball downfield and avoid sacks has him leading statistically. For all the bashing of Sorgi for holding the ball too long and just dinking and dunking, Lorenzen has taken as many sacks, while putting up the worst yards per completion (8.75 to Sorgi's 10 and Gray's 12.7)
Small sample size and different conditions for each QB obviously, but it's always good to take a step back and look at the total production.