A roller collar is provided in a roller assembly of a machine, such as a track carrier roller of a track-type undercarriage. The roller assembly includes a roller mounted on a shaft and having a seal retaining lubricant between the roller and the shaft. The collar and an inner surface of the roller form a seal cavity placing the seal in fluid communication with an ambient atmosphere surrounding the roller. The roller collar extends over an opening into the seal cavity, such as with an outwardly extending flange or teeth or with an outer surface configured to increase a distance to be traveled to enter the seal cavity, and to reduce the amount of abrasive material entering the seal cavity and potentially compromising the integrity of the seal.