Clubs will be restricted to 75 interchanges per match as part of a series of rule changes to the 2021 Toyota AFL Premiership Season.

The new cap on interchange is down from the 90 allowed in 2020. 

In rule changes announced on Wednesday by AFL football operations boss Steve Hocking, the 2021 season will also see an amendment for players standing on the mark, with 50m penalties to be imposed on players who move - outside a one metre "level of tolerance" - laterally off the mark before 'play on' has been called.

Players returning the ball to play after an opposition behind will be given a 15-metre space, an increase of five metres, between them and the opponent standing the mark.

"The main reason (for the 75 interchange cap) is to try and open up congestion around the ground. There are a lot of high pressure game styles which have kicked in, the pressure factors have increased, and have been on the increase for five years now, so our belief is we need to put a little bit of fatigue back into the system, and to recalibrate that part of the game and hopefully have the result of opening up the game," Hocking said.

"We will remain open on how that looks for 2022."

Of the ban on lateral movement by the player on the mark, Hocking said: "We think that will open up the game, it will open up the 45 (degree angle) pass option, which is the best real estate.

"We just want more time and space back in the game, the fans are looking for a better balance between defence and attack, and the game has definitely swayed to towards defence.

"My role in that as custodian of it is to make sure the right things are introduced to open the game back up, and to have more Dustin Martin moments that he did in the Grand Final, where he was able to find space, and we would like to create more of those – that's my role and I'm committed to finding that space."

In 2021, quarter length is expected to return to 20 minutes plus time-on, up from 16 minutes plus time-on in 2020, but the AFL is yet to formally announce that change.

Decisions on the length of the season and the style of fixturing are also to be determined, though clubs have been told there will be a return in 2021 to a minimum 22 matches per club.

Some facets of the AFL industry have sought to play more matches next year as a means to recoup some of the lost revenue of 2020 due to the COVID-19 pandemic.

The regular condensing of matches in the 2020 season emerged as an unexpected positive from the COVID-19 changes, and it is possible the AFL will again look to keep options open on aspects of fixturing for 2021 and beyond.

While deep consideration was given to forcing a set number of players to be anchored in zones at each stoppage, the AFL baulked at introducing such drastic rules for 2021.

It will, though, implement such measures in the newly formed VFL and East Coast second-tier competition, with a minimum of players from each team to be positioned inside each 50m arc - including one per team in each goal goalsquare – at all kick-ins and boundary throw-ins.

Breaches of this rule will result in 50m penalties. The AFL will monitor the workings of this rule and will be prepared to introduce it to the 2022 AFL season.