THE LENGTH of the investigation into Greater Western Sydney's Lachie Whitfield doesn’t concern AFL CEO Gillon McLachlan.

Whitfield, pick No.1 in the 2012 NAB AFL Draft, is under investigation for allegedly seeking to avoid drug testers in May 2015, without advising the Giants he spent nights at former welfare boss Craig Lambert's house. 

McLachlan said he was briefed about the investigation on Tuesday, with the AFL boss revealing he expected the inquiry to wind up in coming days.

By then the evidence will have been handed over to ASADA who will reach a decision on the young Giants midfielder.

"In August (2015) the investigation started and as I understand it, it's been an incredibly detailed, forensic investigation," McLachlan said on Wednesday. 

"There haven't just been simple interviews. There's been forensic orders involved, retrieval of laptops and trying to get to the bottom of it. 

"These things take what they take. They work methodically through it and they don't rush to reach to an outcome." 

Whitfield potentially faces a 2-4 year ban if found guilty of deliberately evading or being involved in seeking to avoid a drug test. 

"The way our process works I didn't have any visibility with it. I was briefed yesterday and it's now known the guys will finish that in the coming days," McLachlan said.

"The report and investigation and what they've compiled will be handed over to ASADA for them to make a decision and I can't really say more than that."

Meanwhile, McLachlan would not be drawn on whether the controversial bye round before the first week of the finals would remain for next season.

Many clubs and coaches have voiced their displeasure about the week off, with Hawthorn coach Alastair Clarkson describing it as a "huge curve ball". 

McLachlan said the week off between games had allowed the individual finals stories to be celebrated.

"We've got time to celebrate stories … here on Wednesday I'm pleased with it," McLachlan said. 

"Let's see how we go until the end of the finals series and we'll make that judgment in the cool light of day."