The AFL's competition committee is considering sweeping rule changes aimed at reducing congestion around the ball and producing a more attractive style of play.
AFL football boss Steve Hocking on Thursday declined to put a timeframe on the introduction of new rules, saying the game may well be left alone in 2019.
But McLachlan has indicated otherwise, saying he expects there to
"There's a board meeting early August and I've got a meeting on Monday afternoon where (Hocking) is going to brief me about where he's at," McLachlan told 3AW radio on Friday.
"I think there'll be some changes. The extent of them, I'm not sure."
Momentum appears to be building for the introduction of starting positions at centre bounces and stoppages, but several coaches have expressed alarm at the idea.
Richmond premiership coach Damien Hardwick said he feared the change would lead to an increase in blowouts, while Collingwood counterpart Nathan Buckley went a step further, saying starting positions would be a "blight" on the game.
"He's not being serious, 'Bucks', is he? He doesn't even know what (the changes) are," McLachlan said.
"Everyone will have their views and everyone's positioning a bit, but what Steve's done is a completely consultative, wide-ranging review.
"I couldn't be more pleased with the way he's gone about it."
The AFL chief indicated that a twilight grand final remained a live possibility in 2019, but said a decision was unlikely to be made until early next year.
McLachlan also weighed in on the future of runners, saying he could see the argument for having them abolished from the game.
Sydney was handed a first and final warning on Thursday after runner Jeremy Laidler stayed out on the field and appeared to be trying to block space during the final minutes of the Swans' win over North Melbourne on Sunday.
"A lot of people are making that point. I'll take the advice of my head of football," McLachlan said.
"If you take an international visitor to the game, they say 'what are those guys running around in pink?' ... they're almost like streakers.
"People quite rightly say we need to get messages out and inform the players ... then there's what some runners do, which is filling holes and getting in the way, and that's not appropriate."
