PORT ADELAIDE forward Lindsay Thomas is facing a lengthy suspension after being referred directly to the Tribunal for his controversial bump on Geelong's Scott Selwood, while the Cat's elder brother Joel has been hit with a one-match suspension for striking Thomas in retaliation.  

Thomas has also been offered a one-match suspension for striking Joel Selwood, but the small forward faces a far longer ban for his bump on Scott in the second quarter of Saturday night's game at Adelaide Oval.  

Thomas charged past the ball to bump the younger Selwood as he crouched over to contest possession, the force of the blow concussing the Cats midfielder and sidelining him for the rest of the game.  

Thomas' conduct was assessed by Match Review Officer Michael Christian as careless, involving severe impact and high contact, which triggered a ban of at least three matches and, thereby, direct referral to the Tribunal.

Christian told reporters on Monday afternoon the impact of Thomas' bump would normally have been classified as high, which would have resulted in a two-match suspension.

"With the potential to cause a more serious injury we decided to upgrade it to severe based around three key factors," Christian said. "The first was the speed at which Thomas was travelling, the second was the position from where he came to bump Selwood and that was from a front-on position, and (there was) also the vulnerability of Selwood."

In addition to his one-match suspension, Joel Selwood was fined $1000 for attempting to trip Power forward Chad Wingard.  

WATCH: Selwood's strike on Thomas

Geelong's midfield was spared a further crippling blow ahead of its round six clash against Sydney when Patrick Dangerfield escaped with a $2000 fine for engaging in rough conduct against Port big man Justin Westhoff.

Tuesday night shapes as a busy one for the Tribunal after Christian also referred Hawks defender James Sicily there on a charge of serious misconduct against North Melbourne's Shaun Atley.  

The charge against Sicily arose from an incident during the second quarter of Sunday's game at Etihad Stadium when he stood on Atley's leg while the Roo was lying face-down on the ground.

"James walked over the lower part of [Atley's] leg and stood on him, put his full weight on him and then continued to walk," Christian said.

"I can't see that it wasn't intentional, but it's important to note that we didn't grade it as such. Serious misconduct is sent straight to the Tribunal.

"From our perspective, it's something that is absolutely unacceptable in the game." 

In better news for the Hawks, star midfielder Tom Mitchell escaped with a $1500 fine on a misconduct charge against Todd Goldstein after elbowing the North ruckman behind play.

WATCH: Tom Mitchell gets Todd Goldstein high

Defender Ryan Burton was given the all-clear for his bump that concussed Shaun Higgins.

"Contact was made from Burton's shoulder into the chest of Higgins. I think it's really important to understand that he took reasonable care to execute the bump fairly. Again, it's something players are permitted to do in the game," Christian said.

"He took all reasonable care to execute the bump fairly and couldn't reasonably foresee that that there was going to be an accidental clash of heads."

WATCH: Burton's bump KO's Higgins

From the same game, Kangaroos forward Cameron Zurhaar was fined $2000 for rough conduct after bumping Hawk David Mirra into Etihad Stadium's fence, Roos defender Majak Daw was fined $1500 for misconduct against Daniel Howe and Hawthorn forward James Cousins was fined $1000 for umpire contact.  

WATCH: Zurhaar bumps Mirra into the fence

Gold Coast midfielder Touk Miller was fined $1500 for misconduct against Brisbane star Dayne Zorko, while fellow Sun Jesse Lonergan was fined $2000 for striking Lion Alex Witherden.