While some of the rule differences between the CFL and the NFL are obvious — three downs instead of four and 12 players instead of 11 on a wider, longer field — there are some subtle nuances that can have a big impact.

Here are three big moments from this year's NFL playoffs that would have been very different had they happened north of the border.

1. During the Jan. 4 wild card game, the Detroit Lions were up 20-17 and in Dallas Cowboy territory when referee Pete Morelli initially announced a pass interference penalty on Cowboys linebacker Anthony Hitchens. Then officials reversed themselves, leaving Detroit facing fourth down. They punted and eventually lost.

How things would be different in the CFL: Coaches are able to challenge pass interference calls — and non-calls — by requesting a video review. Replays showed that Hitchens clearly committed pass interference, which should have resulted in a Detroit first down.

2. The next week in Green Bay, a leaping 31-yard reception by the Cowboy's Dez Bryant on fourth down in the waning minutes — he landed at the one-yard line — was overturned by a Packers challenge. Officials ruled, correctly, that Bryant did not maintain control of the ball throughout the process of contacting the ground and Green Bay went on to a 26-21 victory.

How things would be different in the CFL: A player who catches a ball must only secure possession and perform a football move — something Bryant clearly did. The catch would have stood and Dallas would have been set up on the Green Bay door step with a chance to win the game.

3. The New England Patriots are being accused of deflating the footballs during the AFC championship in order to give quarterback Tom Brady an advantage throwing the ball in bad weather. The ensuing controversy and investigation — which has centred on a Patriots' ball boy making a conspicuous bathroom trip, balls in tow — has caused media firestorm known forever more as "DeflateGate."

How things would be different in the CFL: In the NFL, on-field officials check the inflation levels of the footballs before the game then turn the balls over to the teams for management during the game. In the CFL, league officials control the balls continuously before and during the game, in the possession off-field officials and ball boys paid by the league. Those balls are relayed directly from the ball boys to the officials on the field.