Several clubs are expected to conduct hair testing of players when they return from their holidays in November, with the agreed competition standard that up to 20 players per club can be tested.

Clubs are only told how many players – names are withheld – have used illicit drugs over a three-month period. Any player who tests positive is counselled and then faces regular target testing.

Port Adelaide and Hawthorn, with the endorsement of their leadership groups, were two clubs which lifted the number of pre-season illicit drug tests last summer.

Two club chief executives said they expected more clubs to at least consider adopting that move this year, although they believed the as-yet unratified changes to the illicit drugs policy may be enough to act as a greater deterrent for players.

Players also believe the cross-over seen this season in the Magpies' drug case would have many reconsidering any risky behaviour over the next two months.

Thomas and Keeffe admitted the banned performance-enhancing stimulant clenbuterol probably entered their body while taking illicit drugs in February. This meant they fell under the jurisdiction of the Australian Sports Anti-Doping Authority, and were handed two-year bans, were delisted and fined about $50,000 each by the club.

"ASADA has upped those potential bans for taking a banned substance to four years so that's something players should be aware of," said one club source.

Hawthorn star Sam Mitchell has called for year-round hair testing but not all parties are in favour of that. It appears hair testing will continue to not count as a positive strike under a revised two-strikes system but there is support for it to be used as a way of monitoring those players who have returned a positive urine test.

Players face a four-match ban and a $5000 fine should they record a second positive drug test under the new, but not yet ratified, illicit drugs policy, with the club chief executive then informed. Suspensions would increase to 12 matches under a third-strike.