Fantasy Football Query

I know it has been a couple of weeks since our league's finale, but is there anyone out there that could explain to me how I could lose in Fantasy Football with the following lineup (12 team league):

QB: Tom Brady

RBs: Larry Johnson & Shaun Alexander (picked him up late from an owner that desperately needed a win while he was injured)

WR's: Chad Johnson, Anquan Boldin &/or Marquis Colston

TE: Jeremy Shockey

DEF: Chicago Bears

I picked up Marquis Colston off the waiver wire. I traded Rex Grossman, who was ridin the pine, for Chad Johnson. I traded Warrick Dunn and a player I can't remember for Shaun Alexander. GM of the century, I thought.

Answers???

Apologies to all for my inveterate geekness.