News Ltd papers say there are suspicions that positional selections, such as regular fullbacks starting as forwards, have leaked out of clubs.
Bookmakers are concerned about plunges on bets such as first goalkicker, where inside information can be used by punters to win huge amounts of money.
In the Brisbane-Gold Coast game, Lions full-back Daniel Merrett was a shock starter at full-forward.
He was backed in from $101 to $15 to kick the first goal, leading bookmakers to suspect information about the switch was leaked.
On another occasion, Hawthorn defender Brent Guerra was backed from $101 to $26 to kick the first goal in round 7 against Adelaide.
For that game he played forward and kicked the first point.
The AFL has confirmed that irregularities had been looked at by integrity officer Brett Clothier.
The AFL has urged the federal government to make cheating in sport a crime, punishable by up to 10 years' jail.
The league's general manager of football operations Adrian Anderson said at the launch of Responsible Gambling Awareness Week on Sunday that bribery and corruption have cast a shadow on other sports abroad and the government should introduce laws to protect the integrity of Australian sport.
