For the record and the first play from the line of scrimmage of the game. The Broncos center Ramirez is “awarded” the fumble and not Manning.
From the official game stats:
“(14:53) (Shotgun) 18-P.Manning Aborted. 66-M.Ramirez FUMBLES at DEN 14,...”
Ramirez was probably “awarded” the fumble because Manning never touched the ball. Had Manning even swatted at it on the way by, he would have been tagged with the fumble.