St Kilda's Jake Carlisle will miss the next two matches after the Saints failed to successfully appeal his suspension at the Tribunal.

Carlisle knocked out Richmond forward Jack Riewoldt with a late hit during a marking contest early in their clash on Saturday afternoon, and saw the incident assessed as careless conduct with high impact to the head.

Riewoldt was subsequently ruled out for the remainder of the fixture.

The Saints were unable to overturn the suspension, which will now see Carlisle miss matches against West Coast and Sydney.

St Kilda will also be fined an additional $10,000 for fighting the charge and losing.