The 21-year-old has revealed he was in contention to be upgraded to the senior list before the resignation of coach Brendan McCartney.
Greenwood was one of two Bulldogs cut from the club's rookie list in late October, with Lin Jong and Jack Redpath elevated to the senior list.
Selected as a rookie at the end of season 2011, Greenwood had a steady rise through the VFL ranks, winning a development league premiership with Williamstown in 2013 and then a senior premiership with Footscray this year.
After a solid last two months in the VFL, where he averaged over 20 disposals per game, and a strong finals series, the inside midfielder was on the verge of being elevated to the Bulldogs' senior list but McCartney's untimely resignation changed the course of his future.
"On the Tuesday after the VFL Grand Final I went in and a spoke to list manager Jason McCartney, Brendan and head of football Graham Lowe," Greenwood told AFL.com.au.
"They were happy with the way I finished the year off and played in finals.
"At that point they were still potentially looking at putting me on the senior list, but once Macca resigned that sort of dissipated pretty quickly … but it was a good exit interview."
Several weeks later he was cut from the rookie list and while he has been handed a second chance with an invitation to train with the Bulldogs, the club has made no guarantees about placing him back on the rookie list.
Greenwood said the fact the club still hadn't appointed a senior coach added to the uncertainty of his future.
"I went in and spoke with the club last Thursday," he said.
"They just said if they could, they would have had no hesitation putting me on for a fourth year [on the rookie list] but you just can't legally do that. You can only have three years and then they have to delist you.
"They didn't guarantee anything, but they were certainly very positive about my prospects. As long as I put in a good month's work and nothing really changes then I think I'm a good chance, but there were certainly no guarantees on the table.
"Obviously depending on who the coach is, that might play a part in whether or not I stay around.
"I've got a month to show them what I've got and I believe I can make it. I know I've got a long way to go and I'm not guaranteeing myself anything, but I think if I can get the right opportunity and put my head down only good things can come."
Greenwood has been training five times a week over the past month to make sure he is can make an impact when pre-season starts on Wednesday.
He has also had interest from several VFL clubs, including Footscray, should the Bulldogs decide not to re-rookie him on December 3.