The A-League club have renewed their interest after failing to sign the 33-year-old striker this summer.
"It was a 50-50 thing," he told BBC Scotland. "The club was considering it, I was considering it and, in the end, it didn't come to any fruition.
"Obviously it was something I wanted to explore. The club weren't as keen."
The former Australia international is in his second season of a second spell at Fir Park and signed a new one-year contract in the summer.
But the club managed by former Crystal Palace defender Tony Popovic had hoped to take the former Celtic and Middlesbrough striker back to his homeland for the first time since he left Cranbourne Comets for Southampton in 2000.
Asked if the offer was still alive, McDonald said: "It may well be, but that's not in my hands at all. That would be up to other people to discuss it.
"I haven't heard anything else from representatives or anything else that the deal is still there.
"As far as I'm aware, that club hasn't signed anyone else, so if Motherwell were to change their mind - but that's not happening.
"We are where we are and we resume where we are."
McDonald started on the bench for Motherwell's Scottish Cup defeat by Rangers on 21 January, with manager Mark McGhee later explaining that the striker's "head was not in the right place" because of the transfer approach.
"I offered to play, but we had a conversation and we felt I hadn't trained all week leading up and there was a heavy amount of preparation put into that cup game itself in terms of shape and starting XI," said the striker, who stressed that "the manager and the club have been fantastic to me".
"I agreed it wasn't right for me to step in on Friday and basically call the shots - I'm back in the team.
"That wouldn't be fair on the rest of the squad who had worked really hard during the week as well for me to go and take one of their places and the manager agreed on that.
"Of course, the offer was tempting and that's why it dragged on that whole week."
McDonald returned to the starting line-up for the weekend Premiership loss to Rangers and was sent off after 27 minutes for a foul on Kenny Miller and Well have launched an appeal against the red card.
Western Sydney lie eighth in the 10-team A-League.

The hyperbaric chamber, which treats divers with "the bends", was operated by St John's Ambulance on a donation basis until it broke in April 2014.
The health department replaced it in 2015, but says it needs to "balance the books".
Diving instructor Steve Bougourd said he was "gobsmacked".
"I'm just worried that this kind of cost will put people off of actually going to the [hospital] and notifying them if they suspect a problem," he said.
"We may find it's going to be very expensive to get out divers insured."
In the UK hyperbaric oxygen treatment is covered by the NHS, but Guernsey has its own health care system.
Source: NHS
Assistant director at Guernsey's health and social care department (HSC) Ed Freestone said renting the chamber was costing the government £60,000 a year.
He said the department would not make a profit from the new charges, which were based on "the average usage that we could identify over the previous few years".
In addition to paying for the training of staff and the maintenance of a 24 hour service, the department had to fund plans to buy its own chamber for about £250,000, Mr Freestone said.
Commercial divers already pay a £150 notification fee to dive which raises about £10,000 a year, according to HSC.
It is a legal requirement to provide a hyperbaric chamber facility for commercial diving activity to take place within Guernsey's 12-mile limit.

Media playback is unsupported on your device
16 November 2014 Last updated at 19:39 GMT
Adam Gilmour was walking to meet a school bus with his mother and siblings when the accident happened near Cloughmills on Tuesday.
BBC Newsline's Conor Macauley reports.
Scott McDonald has admitted he was "tempted" by an offer from Western Sydney Wanderers but that Motherwell rejected their latest approach.
[NEXT_CONCEPT]
Divers in Guernsey will be hit with a £30,000 charge if they require treatment for decompression sickness, the government has confirmed.
[NEXT_CONCEPT]
The funeral of the eight-year-old boy who was killed after his family was knocked down by a car on the way to school has taken place in Glarryford, County Antrim.