Rules Analysis
the disc contacts the ground while it is not in the possession of an offensive player (a “down”);
It is not a turnover if a player fumbles the disc prior to fully establishing possession when attempting to gain possession of the disc after a turnover, or after a pull that has already contacted the ground (see rule 8.1.4).
however it is not “down” if a receiver catches a pass before the disc contacts the ground, and maintains the catch while the disc is in contact with the ground.
If a receiver dives to receive a pass and catches the disc before it hits the ground, the disc can contact the ground after that, and still be “up”, as long as the player maintains the catch while the disc is touching the ground. The receiver can change the body parts that are being used to trap the disc, and as long as the disc continues to be trapped by at least one of those sets of body parts during that change, it is considered the same catch. If the receiver has pinched the disc between their fingers, and when the disc hits the ground it caused the disc to move and to no longer be pinched in the same spot, that is not a ‘maintained catch’ and therefore a turnover.If, after catching a disc that then contacts the ground, the receiver subsequently loses control while the disc is no longer touching the ground, the earlier catch is not negated - the disc can still be caught by any player.
the disc contacts the ground while it is not in the possession of an offensive player (a "down");
It is not a turnover if a player fumbles the disc prior to fully establishing possession when attempting to gain possession of the disc after a turnover, or after a pull that has already contacted the ground.