Nigel was in trouble with loan sharks who had threatened to take his pub away unless he started blowing some kicks, ensuring that his team lost the game that would send them to the playoffs. With the game on the line, Nigel knew he had to choose between losing his pub or letting his teammates down. Shane figured it out and decided to run a fake to take the game out of Nigel's hands (or feet) and avoid a lose/lose situation for his kicker.

There's many theories as to why this happens: 1) Martel hates Falco and may have put in his contract to have Shane scratched from the game 2) Management knew the replacement players loved Shane and hated Eddie so they may have asked Shane to leave to avoid controversy 3) O' Neil may have figured that McGuinty would be inclined to play Falco if he were dressed

Wilson Carr is one of the players from the Sentinels team seen in several earlier scenes in the film. He is the man who tells Shane that he not only took Martell's job, but took his parking space too.