Depends on which leg is contacted. If there is no intent to injure and you contact the kicking leg, it is a contacting the kicker penalty (which was called on the play). If you contact the plant leg, then it is a roughing penalty.
CONTACTING / ROUGHING THE KICKER
Rule 7 Section 1 Article 2 outlines the provisions governing Contacting the Kicker:
Rule 7 Section 2 Article 3 identifies the Roughing the Kicker as:
“Unnecessary Roughness against the punter, kicker or the ball holder on a place kick.?
When applying these rules, Referees have been instructed for several years to apply the following:
Contact with the kicking leg, before it returns to the ground, should result in the application of a Contacting the Kicker penalty, unless the contact was severe in nature (in which case Roughing the Kicker would be applied).
Contact with the plant leg, on which the kicker balances, should result in the application of a Roughing the Kicker penalty, regardless of the severity of the contact (contact with the plant leg will almost always take the kicker off his feet)
From the CFL rulebook:
For the 2008 season, the following standards will be applied:
Contact with kicking leg – a Contacting the Kicker penalty
Slight or Incidental contact which does not affect the play – NO foul
Contact with the plant leg – a Roughing the Kicker penalty
If a player blocks or touches the ball, he will not be penalized for Contacting the Kicker
If a player blocks or touches the ball, and commits no other act other than running into the kicker in his attempt to block the kick, he will not be penalized for Roughing the Kicker.