THE WESTERN Bulldogs have until Thursday evening to tell the AFL why runner Rohan Smith spent long periods of time on the ground during Friday night's win over Adelaide at Etihad Stadium.

Smith, a club great who played 300 games for the Dogs between 1992 and 2006, wore a microphone for Channel 7's coverage of the match and was captured on field for extended blocks of time.

His time on field, and the nature of his messages to the players, was held up for scrutiny on Monday night's episode of On the Couch on Fox Sports.

The Dogs now have until close of business on Thursday to explain his actions.

Smith has acted as runner for the club since its round nine clash with West Coast at Patersons Stadium.

In May 2009, then-Port Adelaide runner David Arnfield was suspended for four matches for repeated breaches of AFL legislation.

It was determined Arnfield stepped outside the AFL rule relating to runners being allowed onto the ground "for the sole purpose of conferring briefly with the players of his club [and] ... must then immediately leave the playing surface".

Arnfield had made previous breaches in 2005 and 2006.

The Power were allowed to use a replacement runner during his suspension.